Characteristics of multifactorial diseases. DNA testing: monogenic and multifactorial diseases

General concepts on multifactorial diseases

Genetic information, combined with environmental influences, determines the uniqueness of each person. By “external environment” we mean here the totality of many factors influencing a person’s life, such as bad habits, upbringing, professional activity, physical activity and many, many others.

Genetic (or hereditary) information is contained in the nucleotide sequence of DNA. The DNA strand is tightly packed (coiled) into chromosomes. Each cell of the human body contains 23 pairs of chromosomes. Each pair has one chromosome from the mother and one from the father. The exception is the sex cells (eggs and sperm), which contain one chromosome from each pair. After fertilization of an egg with a sperm, an embryo with 23 pairs of chromosomes is obtained, from which a person develops with a full amount of genetic information.

A DNA molecule is a sequence of nucleotides (“letters”). This sequence of nucleotides encodes hereditary information. As a result of the international Human Genome program in 2003, such a sequence was deciphered for all human chromosomes (with the exception of a number of sections whose decoding is difficult due to their structural features).

Decoding the human genome has shown that the genetic information of two unrelated people is only 99% identical. The remaining 1%, together with the “external environment,” is responsible for the diversity of appearance, abilities, character, and for all the differences between people.

In addition to appearance, character or abilities, a person also inherits the characteristics of his health - resistance to stress, the ability to tolerate physical activity, metabolic characteristics, and tolerance to medications. The uniqueness of hereditary information is manifested in the peculiarities of the functioning of the body at the molecular level. For example, one person may have a certain enzyme that is more active than another, while a third may not have that enzyme at all. Such variations can lead to various diseases, and these diseases are divided into hereditary and multifactorial.

Hereditary diseases

In the case of hereditary diseases, changes in the genome (mutations) directly lead to the development of the disease. That is, if the mutation was passed on by one of the parents, then the person becomes a carrier of the disease, if the mutation was passed on by both parents, then the person will get sick. The most common genetic (or hereditary) diseases include phenylketonuria, hemophilia, color blindness and others. You can find out more about hereditary diseases here (in the pregnancy section there are detailed articles on some tests, including on the diagnosis of genetic diseases).

Hereditary diseases are quite rare; variations in the genome are mainly associated with multifactorial diseases.

Multifactorial diseases- these are diseases that arise from an unfavorable combination of a number of factors: genetic characteristics (genetic predisposition) and the influence of the “external environment” - bad habits, lifestyle, professional activity and others. So-called SNPs (single nucleotide polymorphism - single nucleotide polymorphisms or substitutions) are most often responsible for genetic predisposition. That is, replacing one letter in a DNA strand with another.

In the case of hereditary diseases, we used the term “mutation”, and in the case of multifactorial diseases, “polymorphism”. From a molecular point of view, these are the same thing: quantitative and qualitative changes in the structure of DNA. Their main differences are the frequency of occurrence and the consequences for the body. Within a population, a certain mutation occurs with a frequency of 1-2%. They are either incompatible with life or necessarily lead to the development of the disease. Polymorphisms occur with a frequency of more than 1-2%. They can be neutral (not affect the body in any way), predispose to diseases under certain conditions, or, conversely, to some extent protect against the development of the disease.

That is, the mere presence of a genetic predisposition to a disease will not necessarily lead to the development of this disease. However, in the presence of unfavorable “external environmental” factors, a person with a hereditary predisposition has a significantly greater likelihood of getting sick than people who do not have such a predisposition.

An illustrative example is the predisposition to lung cancer and such an “external environmental” factor as smoking. Everyone knows about the dangers of smoking and that this bad habit can lead to cancer. However, as a refutation of the harm of smoking, you can often hear stories from smokers about how someone smoked two packs of cigarettes a day all their life and lived to be 90 years old. Yes, this happens, but this does not refute the harm of smoking, it suggests that some people are genetically predisposed to developing lung cancer, while others are not. And in combination with such an “external environmental” factor as smoking, hereditary predisposition is likely to lead to the development of cancer.

What can the knowledge that we are genetically predisposed to any disease give us?

You can often hear the opinion that it is better not to know about your predisposition to various diseases - anyway, you can’t change anything, it’s just an extra reason to be nervous. But that's not true!

First, let's remember that the disease occurs in the presence of unfavorable factors in the “external environment.” The influence of these factors can in many cases be excluded. For example, a predisposition to lung cancer is a strong argument in favor of giving up this bad habit.

Secondly, in some cases there are effective methods for preventing a disease to which there is a genetic predisposition. For example, if you are predisposed to thromboembolism, regular use of low doses of aspirin significantly reduces the risk of thrombosis.

Thirdly, it is much easier to treat diseases at an early stage. But at this time the disease is often asymptomatic. Few people have the desire, time and financial resources for a regular full examination of their body. If we know the characteristics of our genome, we know the specific list of diseases to which we are predisposed, it will be easier for us to track these diseases at an early stage.

Fourthly, the presence of a genetic predisposition to a certain disease can affect the treatment regimen for this disease. For example, the regulation of blood pressure is a rather complex process for which a large number of genes are responsible. Depending on which gene change leads to the development of arterial hypertension, the doctor can prescribe the most effective treatment.

There are a large number of normal and pathological traits, the genetic variability of which is quite obvious, but it cannot be explained by a simple Mendelian type of inheritance. However, even with the Mendelian type of inheritance, it is impossible to say with complete certainty that the analyzed gene is the only cause of the trait, since the same phenotype can be caused by mutations in different loci.

Such traits that are difficult to explain using Mendelian inheritance include rare qualitative deviations from the norm and widespread traits. Diseases with a hereditary predisposition are determined by the interaction of hereditary and environmental factors. This group of pathologies is based on a wide genetic balanced polymorphism of human populations in enzymes, structural and transport proteins, and antigens. In human populations, about 25% of loci are represented by two or more alleles. Individual combinations of the latter are varied. The genetic uniqueness of a person is expressed in physical and mental characteristics, reactions to pathogenic environmental factors. Diseases with a hereditary predisposition occur in individuals with a certain genotype, i.e., with a combination of “predisposing” alleles and the provoking effect of environmental factors. In addition, the same gene can, under some conditions, cause an increased and, under other conditions, a decreased ability to reproduce a trait(s).

Diseases with a hereditary predisposition differ from monogenic diseases in that their manifestation requires the action of certain environmental factors.

Monogenic diseases with a hereditary predisposition are determined by one mutant gene, but their manifestation requires the obligatory action of a specific environmental factor, which is specific in relation to this disease.

Considering the important role of environmental factors in the manifestation of these diseases, they should be considered as hereditarily determined pathological reactions to the action of external factors. This may be a perverted reaction to pharmacological drugs, to air pollution, to nutrients and additives, to physical and biological factors.

These diseases are few in number, their prevention and treatment have been developed and are sufficiently effective.

Polygenic diseases with a hereditary predisposition are determined by many genes, each of which is normal rather than altered, and occurs in interaction with environmental factors. The role of genetic and environmental factors is different not only for a specific disease, but also for each person.



Polygenic diseases with a hereditary predisposition make up 90% of chronic non-infectious diseases of various human systems and organs: hypertension, coronary heart disease, diabetes mellitus, peptic ulcer.

In diseases, there is always some combination of mutant genes interacting with each other. An individual who inherits the combination passes the “risk threshold,” meaning that only environmental factors now determine whether and to what extent the disease will develop.

Also, all blood relatives of the patient are at risk of acquiring the same syndrome, since each of them has half of his genes. The more distant the degree of relationship, the less likely it is to inherit a similar combination of genes. And also, the likelihood of inheriting a “risky” combination of genes decreases as the number of genes necessary for the manifestation of the disease increases.

But since identifying genes in combination and calculating their exact number is very difficult and often impossible, calculating the risk of inheritance for the patient’s relatives is based on empirical estimates, that is, on an assessment of the situation in each specific family. The greater the number of affected relatives and the more severe the disease, the higher the risk for other relatives.

There are a number of hypotheses that explain the origin of multifactorial diseases. Traits that contribute to the development of multifactorial diseases include those caused by many genetic and environmental factors that interact with each other in a cumulative (additive) manner.

There are 3 classes of such signs:



1. Characteristics characterized by constant differences. This includes extreme variants of a normal series of characteristics that go beyond the boundaries of normal indicators (below the lower limit or above the upper limit) with deviations from the average values ​​by more than two errors. This class of features is well described using a Gaussian distribution (according to the formula). If most differences in quantitative traits (for example, height, body weight) have a normal distribution in the population (a curve with one vertex) and are the norm (94% of all differences), then a smaller proportion of differences relate to traits characterized by constant differences (6% of differences) .

2. Congenital malformations (CDM) with susceptibility to partial changes that are not accompanied by a clinical effect. These include congenital malformations of a multifactorial nature: neural tube defects (spina bifida, anencephaly), cleft lip, cleft palate, congenital heart defects and great vessels, Klippel-Feil syndrome (anomalies of the cervical vertebrae), Pierre-Robin syndrome (cleft palate , micrognathia, glossoptosis), etc.

3. Chronic widespread diseases of non-infectious nature. These include arterial hypertension, bronchial asthma, coronary heart disease, psoriasis, diabetes mellitus, gastric and duodenal ulcers, rheumatism, schizophrenia, manic-depressive psychosis, many forms of cancer, etc. If we exclude monogenic diseases, chromosomal syndromes, injuries, acute infectious and bacterial diseases, then everything that remains (and this is about 90% of cases of chronic non-infectious human pathology) will be classified as multifactorial diseases.

Multifactorial diseases, with all their diversity, are characterized by some common features: 1) high frequency in the population; 2) the existence of clinical forms that form a continuous series in the population from hidden subclinical to pronounced manifestations; 3) earlier onset and some increase in clinical manifestations in descending generations; 4) significant gender and age differences in the population frequency of nosological forms; 5) a relatively low level of concordance for the manifest manifestations of the disease in monozygotic twins (60% and below), however, exceeding the corresponding level in dizygotic twins; 6) inconsistency of inheritance patterns with simple Mendelian models; 7) the dependence of the degree of risk for the patient’s relatives on the frequency of the disease in the population (it is higher, the less common the disease is), the risk increases with the birth of each subsequent patient, in addition, it increases as the severity of the proband’s disease increases; 8) the similarity of clinical and other manifestations of the disease in close relatives and the proband, which reflects the heritability coefficient (for polygenic diseases it exceeds 50-60%).

Any multifactorial disease is based on several causes. Moreover, the individual contribution (effect) of each cause in the manifestation of the disease may be insignificant, and only their total contribution leads to the development of the disease. For example, in persons with acute ischemic cerebrovascular accident, similar cases of the disease occur in the family; a history often includes arterial hypertension, hypercholesterolemia, physical inactivity, obesity, alcohol and nicotine abuse. More often, stroke occurs in males aged 60-65 years and older.

In many multifactorial diseases, the same pathogenetic mechanism can be triggered in several ways: either by one cause or by a combination of several causes. Some reasons may be genetic (major gene, polygenic complex), others purely environmental (somatic allergens), behavioral (addiction to certain foods) or social (influence of parents, environment).

Congenital malformations are persistent deviations from the normal structure and functions of individual organs or tissues of the body, developing in utero during the process of ontogenesis.

One of the main causes of congenital malformations are changes in the genetic apparatus - mutations that can affect a limited area of ​​a chromosome and lead to a change in one gene (gene mutations), a section of a chromosome with several genes, an entire chromosome (chromosomal mutations) or the entire chromosome set (genomic mutations). Congenital malformations are also caused by the influence of teratogenic factors during pregnancy (some infectious diseases, radioactive radiation, drugs, etc.), which cause disturbances in the processes of reproduction, migration and differentiation of cells.

Types of congenital malformations

According to the etiological principle, congenital malformations are divided into hereditary (formed as a result of mutations), exogenous (arise under the influence of external harmful factors) and multifactorial (arise from the combined influence of genetic and exogenous factors). In addition, all congenital malformations are divided into isolated, affecting one organ, systemic and multiple.

Isolated and systemic congenital malformations are classified according to anatomical and physiological principles: malformations of the central nervous system; defects of the cardiovascular system, defects of the musculoskeletal system, etc. Multiple congenital malformations occur with chromosomal diseases, gene diseases and some other diseases.

Congenital malformations also include: aplasia (agenesis) – complete absence of an organ or part of it (for example, vaginal aplasia); hypoplasia – underdevelopment of an organ or a decrease in its size (for example, uterine hypoplasia); hyperplasia – excessive development of an organ or part of it (for example, macrosomia); ectopia – unusual location of the organ (eg, exstrophy of the bladder); atresia - complete closure or fusion of natural canals and openings (for example, vaginal atresia, atresia of the hieratic canal, atresia of the hymen, etc.); an increase in the number of organs or their parts (eg, polydactyly); fusion between each other organs, and in case of twin pregnancy – identical twins; persistence - preservation of embryonic structures during the period of development when they normally disappear; dysraphism - preservation of embryonic clefts, etc.

Multifactorial diseases (diseases with a hereditary predisposition) include the largest group of diseases - peptic ulcer of the stomach and duodenum, bronchial asthma, diabetes mellitus, schizophrenia, epilepsy, etc. They are sometimes referred to as multifactorial or polyhemic diseases. Multifactorial diseases have a complex inheritance pattern.

Bronchial asthma

Prevalence is from 4 to 8% among the entire population, in the pediatric population - up to 10%.

Bronchial asthma is a disease based on chronic allergic inflammation of the bronchi, accompanied by their hyperreactivity and periodic attacks of difficulty breathing or suffocation as a result of widespread bronchial obstruction caused by bronchoconstriction, hypersecretion of mucus, and swelling of the bronchial wall.

The main predisposing factors - atopy (the general name for allergic diseases, in the development of which a hereditary predisposition to sensitization plays a significant role) and bronchial hyperreactivity - are genetically determined. Recent evidence suggests that three groups of traits (level of specific IgE, level of total IgE and the presence of bronchial hyperreactivity) are inherited independently of each other. The genes that determine the production of specific IgE are localized on the short arm of chromosome 11 (11q13) and are associated with HLA class II alleles. The control of the basal level of total IgE is carried out by the gene cluster of the long arm of chromosome 5 (5q31.1). Bronchial hyperreactivity is associated with genetic markers of the same segment (5q31.1-q33). Each of the genetic predisposition factors increases the likelihood of asthma, and their combination leads to a high risk of developing the disease with minimal participation of environmental factors. The most significant of them are the pathological course of the intrauterine period, prematurity, poor nutrition, pollutants and tobacco smoke, ARVI.

Often asthma is combined with atopic dermatitis, the main predisposing factor of which is also atopy. The risk of developing atopic disease in children (regardless of the form) is 60-80% if both parents are sick and/or have a family history; up to 50% and above - through the mother's side; 25-30% - on the father's side.

Peptic ulcer

Peptic ulcer disease is a chronic recurrent disease characterized by the formation of gastric or duodenal ulcers due to disruption of the general and local mechanisms of nervous and humoral regulation of the basic functions of the gastroduodenal system and trophism, as well as the development of proteolysis of the mucous membrane.

From a genetic point of view, peptic ulcer disease can be divided into four main groups:

1. Peptic ulcer disease in general is a disease with a hereditary predisposition, characteristic of multifactorial inheritance.

2. Peptic ulcer disease, which fits into a monogenic (usually autosomal dominant) type of inheritance.

3. Peptic ulcer as one of the clinical manifestations of several hereditary syndromes.

4. Ulcerative lesions of the gastroduodenal system in certain somatic diseases.

Diabetes

Diabetes mellitus is a disease that is heterogeneous in nature, the etiology and pathogenesis of which involves both internal (genetic, immune) and external (viral infections, intoxications) factors, the interaction of which leads to disruption of carbohydrate metabolism.

The role of genetic factors in the development of diabetes mellitus:

1. Diabetes mellitus, as well as impaired glucose tolerance, is a constant component of approximately 45 hereditary syndromes.

2. The different clinical manifestations and prevalence of diabetes mellitus in ethnic groups are not always explained only by differences in environmental conditions.

3. Among patients with diabetes, there are groups of people with different dependence on insulin.

4. There is diabetes mellitus in adults, which is inherited monogenically in an autosomal dominant manner.

5. Various types of diabetes mellitus can be modeled in experimental animals.

The development of diabetes mellitus is affected by mutations in one or more genes. Formation of a pathological phenotype, i.e. The development of clinical manifestations of diabetes mellitus in the presence of a hereditary predisposition occurs with the obligatory participation of environmental factors. Various stress factors, infections, injuries, and operations are of great importance in the etiology of diabetes mellitus. For insulin-dependent diabetes mellitus, risk factors are some viral infections (rubella, chickenpox, mumps, coxsackie virus, epidemiological hepatitis), and toxic substances. For non-insulin-dependent diabetes mellitus, risk factors are excess body weight, heredity with diabetes mellitus, atherosclerosis, arterial hypertension, dyslipoproteinemia, decreased physical activity, and unbalanced diet.

High-risk groups for diabetes:

1. Monozygotic twin of a patient with diabetes mellitus;

2. A person whose one or both parents are sick or have had diabetes;

3. A woman who gave birth to a child weighing more than 4.5 kg, as well as a dead child with hyperplasia of the islet apparatus of the pancreas.

Irrational drug therapy is one of the most important risk factors for the development of diabetes mellitus.

Drugs acting on carbohydrate metabolism: adrenaline, aminazine, caffeine, salbutamol, surosemide, corticosteroids, thyroxine, growth hormone, ACTH, dopegit, clonidine, trental, PAS, salicylates, butadione, sulfonamides.

Hereditary syndromes accompanied by impaired glucose tolerance or insulin resistance:

Genetic: Louis-Bar syndrome, cystic fibrosis, Fanconi anemia, glucose-6-phosphate dehydrogenase deficiency, glycogenosis type I, gout, hemochromatosis, Huntington's chorea, Lawrence-Moon-Bardet-Biedl syndrome, Prader-Willi syndrome.

Chromosomal: Down syndrome, Klinefelter syndrome, Shereshevsky-Turner syndrome.

Coronary heart disease (CHD)

IHD occurs due to a decrease or cessation of blood supply to the myocardium due to a pathological process in the coronary vessels. The main part of IHD is a multifactorial pathology, characterized by the formation of the disease through the interaction of genetic and environmental factors that lead to the direct causes of IHD: I) spasm of the coronary arteries; 2) atherosclerosis of the coronary vessels. The main pathophysiological mechanism of IHD is the discrepancy between the myocardial oxygen demand and the ability of the coronary blood flow to satisfy them.

Genetically determined risk factors for IHD include:

Gender of the proband: in women, clinical manifestations occur 10-15 years later, this is due to hormonal differences and morphological features of the structure of the collateral vessels of the coronary arteries;

Body type: more often, cardiovascular diseases associated with atherosclerosis occur in individuals with a hypersthenic body type;

Personal characteristics: personality type “A” is described (energy, accelerated pace of work, desire to achieve set goals, people are emotional, susceptible to stress factors), in which the incidence of IHD is observed 2 times more often than with type “B”.

A certain structure of the coronary vessels;

Increased levels of total cholesterol in the blood; high levels of low and very low density lipoproteins (LDL and VLDL) in the blood; low concentration of high density lipoproteins (HDL);

Low activity of LDL receptors;

Disturbances in the blood coagulation system (increased fibrinogen in the blood serum, hereditary deficiency of fibrinolytic activity);

Arterial hypertension;

Diabetes.

Multifactorial diseases are associated with the action of many genes, which is why they are called multifactorial (English factor-gene). The genetics of common chronic diseases in childhood, as well as in adults, remains one of the complex problems of medical genetics.

Diseases with a hereditary predisposition can only be realized through the close interaction of the genetic constitution (polygenes or mopogens) of the individual and environmental factors as integral factors. It is assumed that without environmental factors, genetic predisposition cannot be realized. This is due to the fact that in diseases associated with disruption of the allelic gene system, the norm of reactions and adaptation to various influences are reduced. For example, the formation of hypertension is observed against the background of stress and mental stress; diabetes mellitus - for eating disorders, overeating, obesity, etc.

This group of diseases is difficult to study, since it is necessary to identify not only hereditary and environmental factors, but also to determine their specific weight.

For these purposes, special mathematical methods are currently used to assess the relative contribution of each component to the development of the disease.

The inheritance of multifactorial diseases does not obey the laws of G. Mendel, as is the case with monogenic diseases, but is based on empirical data. Multifactorial diseases are caused by both hereditary factors and largely unfavorable environmental factors. Moreover, this is a close, inseparable interaction. This is the largest group of diseases, which makes up more than 90-92% of the total number of hereditary pathologies. With age, the frequency of this pathology increases. If in childhood the share of multifactorial diseases is about 10%, then in old age it is about 30%. Polygenetic diseases include gastric and duodenal ulcers, rheumatism, coronary heart disease, liver cirrhosis, diabetes mellitus, bronchial asthma, schizophrenia, psoriasis, etc. A high frequency of diseases in the population is found, for example, about 1% of the population suffers from schizophrenia, diabetes mellitus - 5%, allergic diseases - more than 10%, hypertension - about 30%.

The polygenic nature of diseases with a hereditary predisposition is confirmed using genealogical, twin and population methods. The twin method is quite objective and sensitive. When using it, a comparison is made of the concordance of mono- and dizygotic twins or a comparison of the concordance of monozygotic twins raised together or separately. As a result of twin studies, a higher concordance of monozygotic twins was established compared to dizygotic twins for hypertension, myocardial infarction, stroke, rheumatism and other diseases, including a number of infectious ones (tuberculosis, polio, etc.). This indicates a genetic predisposition to these diseases.

To assess risk for multifactorial diseases, empirical data are collected on the population and family frequency of each disease or malformation.

The polygenic inheritance model, like the monogenic disease model, assumes that the likelihood of the disease among the patient's relatives is higher than in the general population. However, in contrast to monogenic forms of pathology, with polygenic inheritance, the implementation of the disease occurs provided that the threshold of accumulation of genetic and environmental influences is exceeded (exceeding the “critical mass”).

Since many genes or even gene complexes are involved in the development of multifactorial diseases, they are difficult for genetic analysis. Each mutation alone cannot cause the development of the disease. The implementation of the hereditary factor through exposure to unfavorable environmental influences is an indispensable condition for the development of multifactorial diseases. Due to the complexity of the nature of this group of diseases and their inconsistency with the classical types of inheritance frequencies, they speak of additive polygenic inheritance with a threshold effect, i.e. the development of the disease is achieved only when the total effect of genes (alleles) exceeds a certain threshold necessary for the development of the trait.

Thus, at a certain threshold, the “peak susceptibility,” in combination with a complex of unfavorable environmental factors, a disease phenotype is created. Based on the theoretical model of polygenic diseases, we can conclude that the likelihood of developing the disease among relatives of patients suffering from a multifactorial disease is much higher than in the general population. The higher the level of influence of environmental factors, the higher the susceptibility, since relatives have a common habitat, especially in relation to relatives of the 1st degree of kinship. It can be hoped that progress in the field of studying the human genome will be of great help in revealing the role of polygenes in the occurrence and formation of diseases with a hereditary predisposition.


TOPIC: MULTIFACTORIAL DISEASES

1. Type of inheritance in which the development of a trait is controlled
several genes:
1. Pleiotropy
2. Polyteny
3. Polyploidy
4. Polymeria

2. For the prevention of multifactorial diseases, the most important:
1. Calculation of the theoretical risk of transmitting the disease to offspring
2. Formation of risk groups for each specific disease
3. Karyotyping
4. Identification of signs of dysmorphogenesis

3. The genetic basis for the formation of quantitative polygenic traits is:
1. Polymeria
2. Codominance
3. Pleiotropy
4. Variable expressiveness
5. Gene repression

4. To predict predisposition to peptic ulcer disease
The most significant criterion for the duodenum is:
1. Blood type AB0
2. Rh blood type
3. Hyperpepsinogenemia
4. Patient's gender
5. Patient's age

TOPIC: CHROMOSOMAL DISEASES

5. As a result of the action of teratogenic factors, the following develop:
1. Gene mutations
2. Aneuploidy
3. Structural rearrangements of chromosomes
4. phenocopies
5. Genocopies

6. In what period of the cell cycle do chromosomes acquire a double structure:
1.G-0
2.G-1
3.S
4.G-2
5. In mitosis

7. An excessively small mouth is described by the term:
1. Micrognathia
2. Micromelia
3. Microstomia
4. Microcoris
5. Synfreeze

8. A synonym for pterygoid folds is:
1. Ptosis
2. Monobrahy
3. Synfreeze
4. Symblepharon
5. Pterygium

9. The most appropriate periods of pregnancy to study levels
alpha-fetoprotein in the blood:
1. 7-10 weeks
2. 16-20 weeks
3. 25-30 weeks
4. 33-38 weeks

10. A woman’s karyotype examination revealed a balanced
Robertsonian translocation 45XX,t(21,14). Chromosomal syndrome in a child:
1. Martina Bella
2. Edwards
3. Patau
4. Down
5. Cat cry

11. Karyotype characteristic of Klinefelter syndrome:
1. 48, ХХХУ
2. 47, ХУУ
3. 46, XY
4. 45, U
5. 47, XXX

12. Karyotype characteristic of the “cry of the cat” syndrome:
1. 45, XO
2.47, ХХУ
3. 46, XX / 47, XX + 13
4. 46, XX, del(р5)
5.47, XX + 18

13.Theoretical risk of having a child with Down syndrome if present
one of the parents has a balanced Robertsonian translocation
45ХХ,t(21,21):
1. 0
2. 10%
3. As in the population
4. 33%
5. 100%

14. The level of alpha-fetoprotein in the blood of a pregnant woman increases when:
1. Down's disease
2. Edwards syndrome
3. Patau syndrome
4. Cystic fibrosis
5. Congenital malformations

15. The zygote is lethal with the genotype:
1. 45, X
2.47, XY + 21
3. 45, 0U
4. 47, ХХУ

16. The risk of having a second child with Down syndrome (47, XX + 21) in a 40-year-old woman:
1. 33%
2. As in the population
3. 0,01%
4. 25%
5. 50%

17. Syndromes caused by abnormalities of the X chromosome are called:
1. Homosomal
2. Genosomal
3. Gonosomal
4. Conversion
5. Polyploid

18. Polysomy on the X chromosome occurs:
1. Only for men
2. Only for women
3. For men and women

TOPIC: DIAGNOSTICS OF HEREDITARY DISEASES.
MEDICAL-GENETIC COUNSELING.

SELECT ONE CORRECT ANSWER:

19. The preclinical stage of Wilson-Konovalov disease can be diagnosed in:
1. Proband
2. Sibs
3. Heterozygous carriers
4. From parents

20. Optimal period for prenatal diagnosis:
1. 6-8 weeks
2. 10-12 weeks
3. 14-16 weeks
4. 26-28 weeks

21. The probability of having a healthy child in parents with neurofibromatosis (autosomal dominant type) with 100% penetrance:
1. 75%
2. 25%
3. 33%
4. 50%
5. 0

TOPIC: TREATMENT AND PREVENTION OF HEREDITARY DISEASES

SELECT ONE CORRECT ANSWER:

22. Postnatal prevention consists of:
1. Prenatal diagnosis
2. Screening programs
3. Artificial insemination

23. At what stage of embryogenesis is exposure to ionizing radiation especially dangerous?
1. 2nd trimester
2. 7-10 week
3. 2-3 week
4. 4-5 week

24.. The main enzyme that carries out the enzymatic synthesis of the gene (DNA):
1. Cytochrome oxidase
2. Revertases
3. Endonucleases
4. RNA polymerases
5. Superoxidases

25. During chemical synthesis of a gene, the following must be known:
1. Type of gene transmission in offspring
2. Crossover percentage
3. Nucleotide sequences of this gene are structural and regulatory)
4. Gene frequency in a population
5. gene mapping

26. For Wilson-Konovalov disease, the main therapeutic agent is:
1. Cytochrome C
2. Prozerin
3. D-penicillamine
4. Nootropil
5. Hepatoprotectors

TOPIC: DISEASES OF EXPANSIONS

SELECT ONE CORRECT ANSWER:

27. Diseases of expansion are otherwise called:
1. Enzymopathies
2. Dynamic mutations
3. Connective tissue diseases
4. Gonosomal
5. Aberrant

28. With Huntington’s chorea, the degenerative process affects:
1. Anterior horns of the spinal cord
2. Pallidum
3. Striatum
4. Varoliev Bridge
5. Brain peduncles

29. Anticipation for expansion diseases is due to:
1. Increasing the frequency of crossing over
2. Increasing the number of tandem triplet repeats
3. Strengthening the broadcast
4. Manifestations of heterosis

TOPIC: MONOGENIC MENDELIZING HEREDITARY DISEASES

SELECT ONE CORRECT ANSWER:

30. With phenylketonuria, the following is detected:
1. Hypotyrosinemia
2. Hypophenylalaninemia
3. Hypoceruloplasminemia
4. Hyper-3,4-dihydrophenylalaninemia

31. Lysosomal storage diseases include:
1. Hyperlipoproteinemia
2. Cystic fibrosis
3. Sphingolipidoses
4. Galactosemia
5. Albinism

32. It is not typical for hepatocerebral dystrophy:
1. Reduced blood ceruloplasmin
2. Increased copper content in the liver
3. Decreased urinary copper excretion
4. Increase in "direct" blood copper

33. Duchenne myopathy is associated with a mutation of the gene responsible for the synthesis of the enzyme:
1. Galactokinases
2. Dehydropteridine reductase
3. Dystrophin
4. Ceruloplasmin

34. The appearance of compound heterozygotes is possible in a marriage of 2 patients:
1. Huntington's chorea
2. Phenylketonuria
3. Duchenne myopathy
4. Testicular feminization

TOPIC: MATERIAL BASES OF HERITAGE

SELECT ONE CORRECT ANSWER:

35. The frequency of crossing over depends on:
1. Number of genes studied
2. Chromosome doublings
3. Distances between genes
4. Rates of spindle formation

36. An enzyme that recognizes a specific sequence of nucleotides in the double helix of DNA molecules is called:
1. Revertase
2. Restriction enzyme
3. RNA polymerase
4. Homogentinase

37. Result of splicing:
1. Construction of a complementary strand of DNA
2. Construction of mature M-RNA
3. Construction of a polypeptide chain
4. Construction of T-RNA

38. The construction of an amino acid sequence in a polypeptide sequence is called:
1. Transcription
2. Processing
3. Polyploidy
4. Broadcast
5. Replication

39. The main enzyme involved in replication:
1. RNA polymerase
2. Revertase
3. Restriction enzyme
4. DNA polymerase

40. Chromosome set is:
1. Phenotype
2. Genotype
3. Karyotype
4. Recombinant

41. Telomere is:
1. Body measure
2. Structure at the end of a chromosome arm
3. Pericentric region of the chromosome
4. Satellite

42. Light stripes on chromosomes when they are differentially stained are:
1. Heterochromatin
2. Euchromatin
3. Coloring error
4. Chiasmus

43. Unit of genetic code:
1. Dinucleotide
2. Triplet
3. Pyrimidine base
4. Intron

44. Splicing is a process:
1. Exon deletion
2. Construction of pre-M-RNA
3. Intron removal
4. Recombinations

45. At a recombination frequency of 4%, the genetic distance between loci is equal to:
1. 1 M
2. 12 M
3. 4 M
4. 10 M
.
46. ​​Coding regions of DNA include:
1. Exons
2. Introns
3. Recons
4. Restriction sites
5. Minisatellites

47. Which chromosomes belong to group C?
1. Large acrocentric
2. Small acrocentric
3. Small metacentric
4. Middle metacentric

48. The process of formation of preM-RNA is called:
1. Replication
2. Broadcast
3. Transcription
4. Elongation
5. Splicing
.
49. Group G includes chromosomes:
1. Large acrocentric
2. Small acrocentric
3. Small metacentric
4. Middle metacentric
5. Large submetacentric

50. The haploid set contains cells:
1. Neurons
2. Hepatocytes
3. Zygotes
4. Gametes
5. Epithelial

51. Selective increase in the number of copies of individual genes is called:
1. Polyploidy
2. Amplification
3. Crossing over
4. Stigmatization

52. To study the role of genetic and environmental factors, the following method is used:
1. Clinical and genealogical
2. Direct DNA probing
3. Microbiological
4. Cytological
5. Twin

53. Decoding the genetic code is associated with the name of the scientist:
1. James Watson
2. Marshall Nirenberg
3. Francis Chris
4. Wilhelm Johann Sen
5. Herman Möller

54. A drug that made it possible to determine in 1956 the exact number (46) of chromosomes in a human karyotype:
1. Colchicine
2. Cytoarsein
3. Phytohemagglutinin
4. Fluorescent dyes

55. The main property of nucleic acid as a storer and transmitter of hereditary information is the ability to:
1. Self-reproduction
2. Methylation
3. Nucleosome formation
4. Double-chain structure

56. Programmed cell death is called:
1. Apoptosis
2. Necrosis
3. Degeneration
4. Chromatolysis
5. Mutation

57. Apoptosis is associated with mutation:
1. Gene P53
2. Ceruloplasmin gene
3. Cystic fibrosis gene
4. Dismutase gene

58. The unit of measurement for the distance between genes is:
1. Morganida
2. Telomere
3. Centromere

59. Nucleotide sequences removed during processing:
1. CEP website
2. Exons
3. Introns
4. RNA polymerase
5. Moutons

60. Congenital malformations due to the action of a teratogen occur during the period:
1. 1-2 weeks
2. 3-4 weeks
3. 18-20 weeks
4. 6-12 weeks
4. 35-38 weeks

61. As a result of splicing, the following is formed:
1. N-RNA
2. M-RNA
3. I-RNA
4. T-RNA

62. The drug colchicine stops cell division at the stage:
1. Anaphases
2. Prophases
3. Metaphases
4. Telophases

63. Recombining, “rearranging” genes include:
1. Immunoglobulin families
2. Multigenic families of actin genes
3. Globin gene families
4. Major histocompatibility complex genes

64. During mitosis, division occurs:
1. Equational
2. Reduction
3. Recombinant

65. When transcription is initiated, RNA polymerase binds to:
1. CEP website
2. Enhancer
3. Terminator
4. Adenyl residue

TOPIC: MUTATIONS

SELECT ONE CORRECT ANSWER:

66. Chromosomal mutations are:
1. Change in the number of chromosomes
2. Changes in chromosome structure discernible using light microscopy
3. Movement of the centromere along the chromosome
4. Heterochromatin imbalance

67. The presence of multiple variants of the chromosome set in one person is called:
1. Polyploidy
2. Chromosism
3. Genetic load
4. Mosaicism

68. Genomic mutations are:
1. Disturbance in gene structure
2. Change in the number of chromosomes
3. Accumulation of intronic repeats
4. Change in chromosome structure

69. Deletion is:
1. Genomic mutation
2. Gene mutation
3. Chromosomal mutation

70. Replacement of individual nucleotides in a DNA chain with others is referred to as:
1. Chromosomal mutations
2. Genomic mutations
3. Gene mutations

71. Genetic load is the sum of mutations:
1. Dominant
2. Neutral
3. Recessive in a heterozygous state
4. All harmful ones
5. Somatic

72. A teratogen is a factor that:
1. Acts on DNA, leaving heritable changes in it
2. Causes changes in the chromosomal apparatus
3. Causes fetal development disorders
4. Determines the appearance of gene copies

TOPIC: TYPES OF TRANSMISSION OF HEREDITARY CHARACTERS. INTERACTION OF GENES. LINKAGE OF GENES. GENETIC HETEROGENEITY. CLINICAL POLYMORPHISM.

SELECT ONE CORRECT ANSWER:

73. Codominance is the interaction between:
1. Alleles of different genes
2. Alleles of the same gene
3. Rare clutch groups
4. Genomes of X and Y chromosomes
5. Gene clusters

74. Proportion of common genes in first cousins:
1. 0
2. 25%
3. 50%
4. 12,5%
5. As in the population

75. The gene that causes hair growth along the edge of the auricle is located on the chromosome:
1. 13
2. U
3. 21
4. X
5. 18

76. Inherited in an X-linked dominant manner:
1. G-6-FDG deficiency
2. Colorblindness
3. Rickets, “resistant to vitamin D”
4. Hemophilia
5. Becker myopathy

77. The probability of having a sick son from a father suffering from hemophilia:
1. 25%
2. 0
3. 50%
4. 100%

78. A woman suffers from amelogenesis imperfecta (brown tooth enamel). The risk of developing the disease in her children:
1. 25%
2. 50%
3. 33%
4. 75%

79. The risk of having a second child homozygous for the gene for an autosomal recessive disease in phenotypically healthy parents:
1. 50%
2. 33%
3. 25%
4. As in the population

80. In St. Petersburg, molecular diagnostics of the following diseases is possible:
1. Landouzy-Dejerine muscular dystrophy
2. Phenylketonuria
3. Down syndrome
4. Alkaptonuria

81. The following diseases can be diagnosed using the cytogenetic method:
1. Wilson
2. Tay-Sachs
4. Edwards
5. Duchenne

83. Type of marriage that is incestuous:
1. Aunt and nephew
2. Cousins
3. Siblings
4. Grandfather and granddaughter

TOPIC: SOME ISSUES IN POPULATION GENETICS

SELECT ONE CORRECT ANSWER:

84. Heterozygous carriage of the sickle cell anemia gene, which determines resistance to malaria, is called:
1. Polygamy
2. Balanced polymorphism
3. Mosaicism
4. Anticipation

85. The basic law of population genetics is the law:
1. Mendel
2. Beadle-Tatuma
3. Hardy-Weinberg
4. Morgana
5. Wright

TOPIC: MULTIFACTORIAL DISEASES

86. Multifactorial diseases are characterized by:
1. autosomal dominant type of inheritance
2. lack of mendelization
3. pronounced clinical polymorphism
4. children get sick more often
5. the possibility of isolating individual forms with the effect of the main gene
6. absence of a single molecular biochemical defect

87. The hereditary predisposition of polygenic diseases is evidenced by:
1.lower concordance in monozygotic twins
2. increased incidence of morbidity in offspring if 2 parents are sick
3. independence from the degree of consanguinity
4. higher risk for relatives of the patient belonging to less frequently affected
his gender
5. high frequency in the population
6. greater risk of developing the disease in relatives with a lower
frequency of the disease in the population

88. Polygenic inheritance is characterized by:
1. manifestation of heterosis
2. anticipation
3. threshold action of genes is unusual
4. additive action of genes is characteristic
5. the manifestation of a trait depends on the interaction of genetic predisposition
ity and environmental factors

89. Markers of predisposition to multifactorial diseases can be:
1. histocompatibility complex antigens / HLA /
2. blood groups of the ABO system
3. polymorphic DNA markers
4. linked pairs of genes

90. Monogenic diseases and reactions with hereditary predisposition:
1. glucose-6-phosphate dehydrogenase deficiency (favism)
2. acute intermittent porphyria
3. deficiency of serum cholinesterase enzymes
4. Tay-Sachs disease

91. Mechanisms of genetic predisposition in epileptic disease:
1. lability of the neuron membrane potential
2. perinatal pathology
3. synchronization of a group of neurons
4. insufficiency of inhibitory GABAergic mechanisms
5. hypoxia during childbirth

92. Polygenically caused congenital malformations:
1. hydrocephalus
2. cleft lip, palate
3. pyloric stenosis
4. congenital hip dislocation
5. Marfan syndrome

93. Genetically determined risk factors for IHD include:
1. increase in blood plasma androstenediol levels
2. increase in total cholesterol levels
3. increased levels of low and very low density lipoproteins
4. lowering the level of high-density lipoproteins
5. arterial hypertension

TOPIC:CHROMOSOMAL DISEASES.

SELECT ALL CORRECT ANSWERS:

94. Down's disease is characterized by:
1. brachycephaly
2. cleft lip and palate
3. Mongoloid eye shape
4. transverse fold on the palm
5. macroglossia

95. Terms denoting an anomaly of the fingers:
1. arachnodactyly
2. brachydactyly
3. polydactyly
4. brachymelia

96. Edwards syndrome is characterized by:
1. trisomy 17 chromosome
2. trisomy 18
3. mosaicism 46 XX/ 47 XX + 18
4. deletion of chromosome 18
5. duplication of chromosome 17

97. Patau syndrome is characterized by:
1. trisomy 14 chromosome
2. trisomy 13
3. deletion of chromosome 18
4. mosaicism 46ХУ/ 47ХУ + 13
5. duplication of chromosome 18

98. Shereshevsky-Turner syndrome is characterized by:
1. primary amenorrhea
2. monosomy X
3. negative sex chromatin
4. identifying symptoms from birth
5. short height

99. Indications for prenatal karyotyping of the fetus are:
1. presence of phenylketonuria in one of the parents
2.birth of a previous child with Down syndrome
3. carriage of a balanced chromosomal rearrangement in one of the parents
4. the age of the pregnant woman is over 35 years old
5. presence of diabetes in one of the parents

100. Down disease is characterized by karyotype changes:
1. 47 ХХУ
2. 46ХУ/47ХУ+21
3. 46ХУ,t (21.14)
4. 47ХХ+21
5. 46ХУ,del (р5)

101. Clinical signs of Klinefelter syndrome:
1. disomy of chromosomes
2. microorchidism
3. aspermia
4. positive sex chromatin
5. tall

102. Syndromes caused by abnormalities of autosomal chromosomes are characterized by:
1. mental retardation
2. presence of signs of dysmorphogenesis
3. congenital anomalies of internal organs
4. no changes in karyotype
5. monosomy

104. Disease for which it is advisable to study sex chromatin:
1. Down syndrome
2. “cry of the cat” syndrome
3. Klinefelter syndrome
4. Shereshevsky-Turner syndrome
5. triplo-X syndrome

105. The following main features are used to identify chromosomes:
1. size of chromosomes
2. location of the primary constriction
3. presence of secondary constriction
4. telomere location
5. streaking in differential staining

TOPIC:DIAGNOSTICS AND TREATMENT OF HEREDITARY DISEASES.

SELECT ALL CORRECT ANSWERS:

106. Medical genetic counseling is mandatory if:
1. the father of the future spouse has hemophilia
2. in the family of a mother with achondroplasia
3. during inbreeding
4. if the mother’s sister has hepatocerebral dystrophy

107. The main tasks of the clinical-genealogical method:
1. establishing the hereditary nature of the disease
2. establishing the type of inheritance
3. calculation of risk for offspring
4. determination of the circle of people who need a detailed examination
5. pregametic prophylaxis

108. Methods used to diagnose enzymopathies:
1. buccal test
2. cytological
3. biochemical
4. microbiological
5. cytogenetic
6. molecular diagnostics
7. immunological

109. Direct molecular diagnosis of a mutant gene is possible if:
1.gene mapped
2. gene sequenced
3. mutation identified
4. the presence of a proband is mandatory
5. there are DNA probes for a mutant or normal gene
6. the object of research is the gene itself

110. The material for carrying out the polymerase chain reaction can be:
1. chorion cells
2. microorganisms
3. biological fluids (sperm, saliva)
4. old blood stains
5. venous blood
6. embryo at the pre-implantation stage

111. Implementation of the indirect method of molecular diagnostics (RFLP) is possible if:
1. the desired gene is mapped
2. mutation not identified
3. the gene has not been sequenced
4. proband is absent
5. the nucleotide sequences flanking the gene and to them are known
DNA probes or oligoprimers available

112. Etiological methods of treatment include:
1. target organ transplantation
2. genetic engineering
3. introduction of embryonic cells
4. limiting the introduction of a harmful product
5. replacement therapy

113. Pathogenetic therapy includes:
1. autogenotherapy
2. removal of harmful product
3. replacement therapy
4. diet therapy

114. How vector molecules can be used:
1. plasmids
2. yeast
3. phages
4. chromosomes
5. liposomes

115. Prevention of hereditary diseases includes the following levels:
1. pregametic
2. pre-implantation
3. segregation
4. prenatal
5. postnatal
6. during childbirth

TOPIC: MONOGENIC HEREDITARY DISEASES. DISEASES OF EXPANSION.

SELECT ALL CORRECT ANSWERS:

116. Diseases of expansion include:
1. Huntington's chorea
2. Wilson-Konovalov disease
3. Martin-Bell syndrome
4. myotonic dystrophy
5. Erb's myopathy
6. chromosomal diseases

117. Huntington’s chorea is characterized by:
1. preservation of intelligence
2. choreic hyperkinesis
3. dementia
4. onset of the disease at a late age
5. localization of the gene on 12p 16.1-3.
6. increase in triplet repeats

118. Martin-Bell fragile chromosome syndrome is characterized by:
1. localization of the gene on Xq 27-28.
2. mental retardation
3. men get sick more severely
4. increase in triplet repeats
5. microorchidism

119. Hereditary aminoacidopathies include:
1. alkaptonuria
2. phenylketonuria
3. Gaucher disease
4. albinism
5. galactosemia

120. Tay-Sachs disease is characterized by:
1. optic nerve atrophy
2. “salt and pepper” symptom
3. cherry pit symptom
4. dementia
5. lack of lysosomal hydrolase
6. lack of lipoprotein lipase

121. Phenylketonuria is characterized by:
1. autosomal recessive type of inheritance
2. autosomal dominant type of inheritance
3. hyperphenylalaninemia
4. hypophenylalaninemia
5. dementia
6. convulsive syndrome
7. polyneuropathic syndrome

122. To diagnose phenylketonuria use:
1. molecular DNA probing
2. Guthrie microbiological test
3. determination of phenylalanine hydroxylase content
4. Determination of phenylalanine content in the blood
5. determination of phenylalanine content in urine

123. The following are subject to examination for cystic fibrosis:
1. patients with chronic pulmonary pathology
2. patients with pseudomonas infection
3. patients with staphylococcal infection
4. women with primary infertility
5. babies not doubling their body weight by 7 months

TOPIC: MATERIAL FOUNDATIONS OF HERITAGE.
BASICS OF MOLECULAR GENETICS.

SELECT ALL CORRECT ANSWERS.

124. Forms of interaction between allelic genes:
1. incomplete dominance
2. polymer
3. epistasis
4. complete dominance
5. codominance
6. overdominance

125. Forms of interaction of non-allelic genes:
1. codominance
2. overdominance
3. epistasis
4. polymer
5. complementarity

126. During meiosis, division occurs:
1. equational
2. reduction
3. reduction-equation
4. recombinant (crossing over)

127. The main repair enzymes include:
1. restriction enzyme
2. ligase
3. DNA polymerase
4. gangliosidase
5. reversease

128. Complementary to each other are:
1. cytosine - thymine
2. guanine - cytosine
3. adenine - guanine
4. cytosine - adenine
5. adenine - thymine
6. adenine - uracil

129. The most important properties of the genetic code:
1. dipletity
2. triplicity
3. tetrapleth
4. degeneracy
5. versatility
6. extrapolation
7. overlap

130. Regulatory elements of a structural gene include:
1. CEP website
2. promoter
3. reversease
4. enhancer
5. terminator
6.anticodon

131. Heterochromatin is represented by:
1. exons
2. dark stripes with differential staining of chromosomes
3. introns
4. gene elements that ensure cell viability

132. Methods of working with DNA:
1. hybridization of somatic cells
2. creation of recombinant molecules
3. Southern blot hybridization
4. creation of DNA probe libraries
5. polymerase chain reaction
6. Plasma protein electrophoresis
7. genealogical analysis

133. How genetic markers can be used:
1. chromosome polymorphism (morphological rearrangements)
2. linked traits in pedigrees
3. polymorphic restriction sites (DNA markers)
4. blood groups
5. genomic DNA fingerprint
6. HLA complex
7. triplet code

134. Methods for molecular diagnostics of hereditary diseases:
1. direct DNA probing
2. RFLP
3. genomic fingerprinting
4. dermatoglyphics
5. karyotyping
6. determination of sex chromatin

135. Function of protein P 53:
1. lengthens the presynthetic period
2. increases the postsynthetic period
3. stops mitosis
4. induces the synthesis of repair proteins
5. determines apoptosis

136. The genomic library is presented:
1. genetics study guide
2. a set of DNA probes as part of recombinant molecules
3. a set of oligoprimers to the flanking regions of the gene
4. DNA probes to restriction sites
5. collection of clones of known chromosomes
6. DNA viruses

137. Gene expression levels:
1. broadcast
2. transcription
3. processing
4. crossing over
5. post-translational
6. pretranscriptional

138. Sense coding regions of DNA are represented by:
1. unique nucleotide sequences
2. repeating sequences of nucleotides
3. gene clusters
4. restriction sites
5. minisatellites

139. Non-coding DNA is characterized by:
1. representation of repeating sequences
nucleotides
2. participation in the broadcast
3. participation in regulatory functions
4. conservation during splicing
5. use as genetic markers

TOPIC: MUTATIONS.

SELECT ALL CORRECT ANSWERS:

140. Chromosome mutations include:
1. transversion
2. broadcast
3. deletion
4. inversion
5. mimicry
6. translocation
7. extrapolation
8. duplication

141. The following products have antimutagenic properties:
1. mushrooms
2. nuts
3. cabbage
4. bow
5. chicory
6. cognac

142. Drug mutagens include:
1. some antibiotics
2. anticonvulsants
3. psychotropic drugs
4. valerian
5. hormones
6. vitamins

143. Chemical mutagens are characterized by:
1. presence of an action threshold
2. dependence on the individual characteristics of the body
3. dependence on the stage of cell development
4. dependence on the chemical structure of the mutagen
5. dependence on the amount of mutagen

144. The antimutagenic defense system in the body includes:
1. cytochrome C
2. serotonin
3. glutathione
4. heparin
5. vitamin E
6. histamine

TOPIC: MEDICAL AND GENETIC COUNSELING.

SELECT ALL CORRECT ANSWERS:

145. Autosomal dominantly inherited:
1. dystrophic dwarfism
2. Huntington's chorea
3. Erb's myopathy
4. Landouzy-Dejerine myopathy
5. neurofibromatosis

146. Myopathy is inherited linked to the X chromosome:
1. Becker
2. limb-girdle Erba
3. hypertrophic Duchenne
4. humeroscapular-facial Landouzi-Dejerine

147. Genetic heterogeneity is due to:
1. different mutations in one locus
2. chromosomal aberrations
3. disturbance at different levels of gene expression
4. influence of external environmental factors
5. mutations in different loci

148. Clinical polymorphism is caused by:
1. genetic heterogeneity
2. influence of external environmental factors
3. gene interaction
4. genomic mutations

149. Linked genes are characterized by:
1. localization on one chromosome
2. joint transmission of traits does not depend on crossing over
3. joint transmission of traits across generations
4. coding of various features

150. The autosomal dominant type of inheritance is characterized by:
1. absence of illness in parents
2. presence of the disease in all generations of the pedigree
3. manifestation in a heterozygous state
4. independence of the manifestation of the disease from gender
5. in the homozygous state, increased manifestations of the disease
6. always the same expressiveness and penetrance

151. The autosomal recessive type of inheritance is characterized by:
1. parents are phenotypically healthy
2. parents are obligate heterozygous carriers
3. with multiple allelism, the appearance of
"compound heterozygous"
4. inbreeding does not affect gene frequency
5. accumulation of the gene in the population is unusual

152. Recessive X-linked inheritance is characterized by:
1.daughters of a sick father do not receive the disease gene
2.daughters of a sick father are obligate carriers of the gene
3. males are sick
4. In a carrier woman, 25% of sons may be sick
5. 25% of sick sons have a sick father

153. The X-linked dominant type of inheritance is characterized by:
1. the incidence of the disease in men and women is the same
2. a man passes his disease to his son in 50% of cases
3. A sick father passes the disease on to 50% of his daughters.
4. The disease in men is usually milder
5. a woman passes her disease on to 25% of her daughters and sons

TOPIC: POPULATION GENETICS.

SELECT ALL CORRECT ANSWERS:

154. The Hardy-Weinberg law allows you to calculate the frequency:
1. recessive gene
2. dominant gene
3. heterozygous carriage
4. crossing over
5. mutations

155. Genetic-automatic processes include:
1. natural selection
2. mutation process
3. genetic drift
4. inbreeding
5. gene migration
6. Gene linkage

TOPIC: MUTATIONS. CHROMOSOMAL DISEASES.

MATCH:

156. Type of mutation: Name:
1. Numerical A. Deletion
B. Polysomy
2. Structural B. Polyploidy
G. Translocation
D. Aneuploidy

157. Type of mutation: Characteristic features:
1. Gametic A. Passed on by inheritance
2. Somatic B. They are the cause of mosaicism
B. Not inherited

158. Characteristic of a chromosome: Name:
1. Structure at the end of the arm A. Centromere
2. Short arm B. Telomere
3. Long shoulder V.R
4. Primary constriction G. q
5. Secondary constriction D. Satellite

159. Name of the syndrome: Genotype:
1. Patau A. 47 XX + 21
2. Dauna B. 47 XY + 13
3. Edwards V. 47 XXX
4. Triplo-X G. 47 XX + 18

160. Syndrome: Signs:
1. Dawna A. Pterygium
2. Shereshevsky-Turner B. Flattening of the facial profile
B. Short stature
D. Tall
D. Epicanthus
E. Only women suffer
G. Frequent heart defects
H. Mild intellectual impairment
I. Gross intellectual impairment

TOPIC: MONOGENIC DISEASES.

MATCH:

161. Disease: Sign:
1. Huntington's chorea A. Increase in repeat of CGG triplets
2. Martin-Bell syndrome B. Increase in repeat of CAG triplets
B. Gene frequency in men is 1: 1500
D. Mental retardation
D. Presence of signs of dysmorphogenesis

162. Disease: Biochemical defect:
1. Cystic fibrosis A. Impairment of copper transport ATPase
2. Wilson's disease B. Lysosomal hydrolase deficiency
3. Type 1 hyperlipidemia B. Insufficiency of lipoprotein lipase
4. Tay-Sachs disease G. impaired chlorine reabsorption

163. Disease: Diagnostic method:
1. Phenylketonuria A. Sweat test
2. Galactosemia B. Determination of phenylalanine content
3. Cystic fibrosis B. The appearance of typical clinical symptoms
ptomov after drinking milk
D. Determination of enzyme activity
pancreas

164. Disease: Treatment:
1. Wilson's disease A. Exclusion of fructose and sucrose from food.
2. Phenylketonuria B. Reducing cholesterol content in food
3. Familial hyperlipo- B. Consumption of protein hydrolysates
proteidemia G. D-penicillamine
4. Fructosemia

Disease: Symptoms:
1. Cystic fibrosis A. Joint pain
2. Phenylketonuria B. Dementia
3. Tay-Sachs disease B. Blindness
4. Alkaptonuria G. Chronic broncho-pneumonia
D. Dark coloration of cartilage (nose, ears)
E. Pancreatitis

166. Disease: Type of inheritance:
1. Type 1 hyperlipidemia A. Autosomal recessive
2. Fructosemia B. X-linked
3. Albinism B. Autosomal dominant
4. Hunter's mucopolysaccharidosis

167. Disease: Localization of the gene in the chromosome:
1. Huntington's chorea A.H
2. Duchenne myopathy B. 4p
3. Wilson's disease V. 13
4. Cystic fibrosis G. 7

168. Process: Enzyme:
1. DNA cutting A. Revertase
2. DNA cross-linking B. DNA polymerase
3. Construction of a DNA strand based on M-RNA B. Restriction enzyme
4. Construction of a DNA strand based on the DNA strand of G. Ligase
D. Aldolaza

TOPIC: MULTIFACTORIAL DISEASES. POPULATION GENETICS.

MATCH:
169. Disease: HLA marker:
1. Multiple sclerosis A. B8B18 DR3/DR4
2. Insulin-dependent diabetes mellitus B. B27
3. Bekhterev's disease V. A3 B7 DR2

170. Type of marriage: Name:
1. Between royalty A. Assortative
2. By external similarity B. Morganic
3. Between 1st degree relatives B. Incest
4. Between relatives of the 11th degree G. Inbreeding
D. Polygamy

TOPIC: FUNDAMENTALS OF MOLECULAR GENETICS.

171. Stages of gene expression:
1. Post-translation period
2. Splicing
3. Transcription
4. Broadcast

172. Stages of polymerase chain reaction:
1. DNA preparation and purification
2. DNA amplification (increase in quantity)
3. Denaturation by heating (division into 2 chains)
4. Adding DNA polymerase to the solution
5. Annealing (adding artificial specific oligoprimers)

173. Stages of genomic fingerprinting:
1. DNA processing with specific restriction enzymes
2. Electrophoresis
3. Obtaining DNA (e.g. from biological fluids)
4. Hybridization with artificial DNA probes (radioactive markers)
5. Blotting (printing on a nitrocellulose filter)
6. Analysis of variable bands (DNA sections); % coincidence calculation

174. Stages of genetic engineering:
1. Introduction of a recombinant molecule into the recipient cell
2. Creation of a recombinant molecule
3. Analysis of exogenous DNA expression (efficiency analysis)
4. Artificial gene synthesis or isolation of a natural gene
5. Selection of vector molecule

175. Karyotyping stages:
1. Blood collection
2. Staining with Giemsa or fluorescent dyes
3. Place the leukocyte culture in a thermostat (37C) for 3 days
4. Addition of colchicine
5. Introduction to phytohemagglutinin culture
6. Placement in a hypotonic solution
7. Transfer to a glass slide
8. Chromosome identification

TOPIC: MONOGENIC DISEASES.

ESTABLISH SEQUENCE:

176. Clinical syndromes of diagnostic value in Wilson's disease
(in descending order of importance):
1. Damage to the extrapyramidal system
2. Violation of copper metabolism
3. Damage to the liver and other internal organs

177. Pathogenetic changes in Wilson's disease:
1. Impaired copper excretion
2. Damage to the central nervous system
3. Liver damage
4. Damage to the kidneys and other internal organs

178. Medical actions when detecting phenylketonuria:
1.Determination of phenylalanine in blood by chromatographic method
2. Prescribing a special diet
3.Screening microbiological test

179. Medical actions during medical genetic counseling of families with
suspicion of the possibility of having a child with Tay-Sachs disease:
1. Prenatal diagnosis using amniocentesis
2. Examination of a pregnant woman for heterozygous carriage
mutant gene
3. Examination of a woman’s partner for heterozygous carriage
mutant gene
4. Doctor's advice on terminating pregnancy or abandoning the child

180. Pathogenetic changes in fructosemia:
1.Impaired release of glucose from the liver
2.Hypoglycemia
3.Fructokinase deficiency
4. Impaired breakdown of fructose supplied with food

ADD:

181. Strengthening the manifestations of monogenic hereditary and multifactorial
diseases in offspring is called _________________.

182. When determining the degree of empirical risk of disease for relatives 1
degree, the formula ________ can be used.

183. The vertical fold at the corner of the eye is called _____________.

184. A chromosomal abnormality in which some cells retain a normal karyotype, while others have an abnormal one, is called _____________.

185. Karyotype of the parents of a patient with simple trisomy of chromosome 21 _______ _______

186. Type of transmission of hepato-cerebral dystrophy _______- _________.

187. A positive Fehling reaction is detected in cases of ________________ disease.

188. A disease characterized by dark spots on diapers is called ________

190. The patient from whom the pedigree begins is called ___________.

191. The proband’s brothers and sisters are called _________.

192. Artificially created short sequences of nucleotides, complementary
certain sections of DNA are called ______________.

193. A microorganism capable of transferring foreign DNA into a cell and providing
there its replication is called __________ ___________.

194. An artificially created vector with antibodies to the organ “sewn” to it
the target is called ____________.

195. Currently, gene gene methods approved in clinical practice
engineering includes autogenotherapy of ____________ cells.

196. Structure consisting of a host molecule (phage, virus) and a vector molecule
(plasmid, yeast) is called _____________ ___________.

197. Mutations, the appearance of which in a gene increases the ability to further
mutations of the same gene are called ______________.

198. In case of cystic fibrosis, an increased content of ______ is detected in the sweat fluid

199. Patients with chronic bronchopulmonary pathology are subject to examination
on _____________ .

200. The combination of idiocy and blindness is typical for the clinical picture of the disease
_______ - ________ (by last name)

201. Cell division that determines genetic variability is called ___________.

202. Individual map of repeating sequences (minisatellites)
inherent in every person is called _____ - _________.

203. Removal of introns during the conversion of I-RNA into M-RNA is called ____________.

204. Determining the nucleotide sequence of a gene is called _______________.

205. Alternative forms of the same gene are called ___________.

206. A drug that stops cell division at the metaphase stage is called ________.

207. The unit for measuring the distance between loci (genes) is called ____________.

208. Selective increase in the number of copies of individual nucleotides (genes), for example
with PCR it is called _____________.

209 Transfer of information recorded on DNA strands through RNA to polypeptide
The protein chain is called ___________ _______.

210. Protection of DNA from the action of its own restriction enzymes is called ______________.

211. Sense (coding) sections of DNA make up ____ - ____ percent
(range in numbers)

212.Another name for “jumping” genes that can be integrated into DNA __________.

213. Mutations that lead to the death of an organism at the zygote stage are called ________.

214. In the presence of Down's disease in the fetus, the level in the blood of a pregnant woman
-fetoprotein _____________.

215. A change in the number of chromosomes in one of the pairs is called _______________.

216. Interaction of allelic genes, each of which manifests itself phenotypically
called ________________.

217. Marriage between 1st degree relatives is called ____________.

218. The presence of eunuchoid structural features in tall men with psychopathic
deviations characteristic of the syndrome ______________ (last name)

219. Marriage based on external similarity is called ________________.

220. The genetic program that determines the development of an individual is called ___________.

221. The totality of all chromosomes containing units of heredity (genes)
called __________.

222. The external manifestation of the implementation of a gene is called ____________.

223. Inheritance associated with the X chromosome is called ______________.

224. Inheritance associated with the Y chromosome is called ______________.

225. The law of constancy and balance of genotypes in a population is called the law
________ - _________ .(by last name)

Monogenic diseases with a hereditary predisposition are also determined by a single mutant gene, but their manifestation requires the mandatory action of a specific environmental factor, which can be considered specific in relation to a given disease. These diseases are relatively few in number, they are inherited according to Mendelian laws, their prevention and treatment are sufficiently developed and effective. Considering the important role of environmental factors in the manifestation of these diseases, they should be considered as hereditarily determined pathological reactions to the action of external factors. This may be a perverted reaction to pharmacological drugs sulfonamides, primaquine, etc., to air pollution polycyclic hydrocarbons, to nutrients and additives lactose, chocolate, alcohol, to physical cold, ultraviolet rays and biological vaccines, allergen factors.

Causes of gene pathologies

Most gene pathologies are caused by mutations in structural genes that perform their function through the synthesis of polypeptides - proteins. Any gene mutation leads to a change in the structure or quantity of the protein.
The onset of any gene disease is associated with the primary effect of the mutant allele.

The basic scheme of gene diseases includes a number of links:
mutant allele > altered primary product > chain of biochemical processes in the cell > organs > organism

As a result of a gene mutation at the molecular level, the following options are possible:
abnormal protein synthesis

production of excess amounts of gene product

lack of primary product production

production of a reduced amount of normal primary product.

Without ending at the molecular level in the primary links, the pathogenesis of gene diseases continues at the cellular level. In various diseases, the point of application of the action of the mutant gene can be either individual cell structures - lysosomes, membranes, mitochondria, peroxisomes, or human organs.

Clinical manifestations of gene diseases, the severity and speed of their development depend on the characteristics of the body’s genotype, the patient’s age, environmental conditions, nutrition, cooling, stress, overwork and other factors.

A feature of genetic diseases, as well as all hereditary diseases in general, is their heterogeneity. This means that the same phenotypic manifestation of a disease can be caused by mutations in different genes or by different mutations within the same gene. The heterogeneity of hereditary diseases was first identified by S. N. Davidenkov in 1934.

The overall frequency of gene diseases in the population is 1-2%. Conventionally, the frequency of gene diseases is considered high if it occurs with a frequency of 1 case per 10,000 newborns, average - 1 per 10,000 - 40,000, and then low.

Monogenic forms of gene diseases are inherited in accordance with the laws of G. Mendel. According to the type of inheritance, they are divided into autosomal dominant, autosomal recessive and linked to the X or Y chromosomes.

Classification
Genetic diseases in humans include numerous metabolic diseases. They may be associated with metabolic disorders of carbohydrates, lipids, steroids, purines and pyrimidines, bilirubin, metals, etc. There is not yet a unified classification of hereditary metabolic diseases.
Amino acid metabolism diseases

The largest group of hereditary metabolic diseases. Almost all of them are inherited in an autosomal recessive manner. The cause of diseases is the deficiency of one or another enzyme responsible for the synthesis of amino acids.

These include:
phenylketonuria - impaired conversion of phenylalanine to tyrosine due to a sharp decrease in the activity of phenylalanine hydroxylase

alkaptonuria - a disorder of tyrosine metabolism due to reduced activity of the enzyme homogentisinase and the accumulation of homotentisic acid in the tissues of the body

oculocutaneous albinism is caused by the lack of synthesis of the enzyme tyrosinase.

Carbohydrate metabolism disorders
galactosemia - absence of the enzyme galactose-1-phosphate-uridyltransferase and accumulation of galactose in the blood

Glycogen disease is a disorder of the synthesis and breakdown of glycogen.

Diseases associated with lipid metabolism disorders
Niemann-Pick disease - decreased activity of the enzyme sphingomyelinase, degeneration of nerve cells and disruption of the nervous system

Gaucher disease is the accumulation of cerebrosides in the cells of the nervous and reticuloendothelial system, caused by a deficiency of the enzyme glucocerebrosidase.

Hereditary diseases of purine and pyrimidine metabolism
gout

Lesch-Nyhan syndrome.

Connective tissue metabolic disorders
Marfan syndrome "spider"

fingers", arachnodactyly - damage to connective tissue due to a mutation in the gene responsible for the synthesis of fibrillin

mucopolysaccharidoses are a group of connective tissue diseases associated with impaired metabolism of acid glycosaminoglycans.
Fibrodysplasia is a connective tissue disease associated with its progressive ossification as a result of a mutation in the ACVR1 gene

Inherited disorders of circulating proteins
hemoglobinopathies are hereditary disorders of hemoglobin synthesis. There are quantitative structural and qualitative forms. The former are characterized by a change in the primary structure of hemoglobin proteins, which can lead to disruption of its stability and function (sickle cell anemia). In high-quality forms, the structure of hemoglobin remains normal, only the rate of synthesis of thalassemia globin chains is reduced.

Hereditary diseases of metal metabolism
Konovalov-Wilson disease, etc.
Syndromes of malabsorption in the digestive tract
cystic fibrosis

lactose intolerance, etc.
Chromosomal diseases include diseases caused by genomic mutations or structural changes in individual chromosomes. Chromosomal diseases arise as a result of mutations in the germ cells of one of the parents. No more than 3-5% of them are passed on from generation to generation. Chromosomal abnormalities account for approximately 50% of spontaneous abortions and 7% of all stillbirths.
All chromosomal diseases are usually divided into two groups: abnormalities in the number of chromosomes and disturbances in the structure of chromosomes.
Chromosome number abnormalities
Diseases caused by a violation of the number of autosomes of non-sex chromosomes
Down syndrome - trisomy 21, signs include: dementia, growth retardation, characteristic appearance, changes in dermatoglyphics

Patau syndrome - trisomy on chromosome 13, characterized by multiple malformations, idiocy, often - polydactyly, structural abnormalities of the genital organs, deafness; Almost all patients do not survive to one year

Edwards syndrome - trisomy on chromosome 18, the lower jaw and mouth opening are small, the palpebral fissures are narrow and short, the ears are deformed; 60% of children die before the age of 3 months, only 10% survive to one year, the main cause is respiratory arrest and disruption of the heart.
Diseases associated with a violation of the number of sex chromosomes
Shereshevsky-Turner syndrome - the absence of one X chromosome in women 45 XO due to a violation of the divergence of sex chromosomes; signs include short stature, sexual infantilism and infertility, various somatic disorders of micrognathia, short neck, etc.

polysomy on the X chromosome - includes trisomy 47, XXX, tetrasomy 48, XXXX, pentasomy 49, XXXXX, there is a slight decrease in intelligence, an increased likelihood of developing psychosis and schizophrenia with an unfavorable type of course

Y-chromosome polysomy - like X-chromosome polysomy, includes trisomy 47, XYY, tetrasomy 48, XYYY, pentasomy 49, XYYYY, clinical manifestations are also similar to X-chromosome polysomy

Klinefelter syndrome - polysomy on the X- and Y-chromosomes in boys 47, XXY; 48, XXYY, etc., signs: eunuchoid type of build, gynecomastia, weak hair growth on the face, in the armpits and pubic area, sexual infantilism, infertility; mental development is lagging behind, but sometimes intelligence is normal.
Diseases caused by polyploidy
triploidy, tetraploidy, etc.; the reason is a disruption of the meiosis process due to mutation, as a result of which the daughter sex cell receives instead of the haploid 23, a diploid 46 set of chromosomes, that is, 69 chromosomes in men, karyotype 69, XYY, in women - 69, XXX; almost always lethal before birth.
Chromosome structure disorders

Translocations are exchange rearrangements between non-homologous chromosomes.
Deletions are the loss of a section of a chromosome. For example, “cry of the cat” syndrome is associated with a deletion of the short arm of chromosome 5. Its sign is the unusual crying of children, reminiscent of the meowing or cry of a cat. This is due to pathology of the larynx or vocal cords. The most typical, in addition to the “cry of a cat,” is mental and physical underdevelopment, microcephaly, an abnormally small head.
Inversions are rotations of a chromosome section by 180 degrees.
Duplications are doublings of a chromosome section.
Isochromosomy - chromosomes with repeated genetic material in both arms.
The appearance of ring chromosomes is the connection of two terminal deletions in both arms of a chromosome.

Currently, more than 700 diseases are known in humans caused by changes in the number or structure of chromosomes. About 25% are due to autosomal trisomies, 46% are due to sex chromosome pathology. Structural adjustments account for 10.4%. Among chromosomal rearrangements, translocations and deletions are the most common.

Previously, polygenic diseases - diseases with a hereditary predisposition are caused by both hereditary factors and, to a large extent, environmental factors. In addition, they are associated with the action of many genes, which is why they are also called multifactorial. The most common multifactorial diseases include: rheumatoid arthritis, coronary heart disease, hypertension and peptic ulcers, liver cirrhosis, diabetes mellitus, bronchial asthma, psoriasis, schizophrenia, etc.

Polygenic diseases are closely associated with inborn errors of metabolism, some of which may manifest as metabolic diseases.

Distribution of polygenic hereditary diseases
This group of diseases currently accounts for 92% of the total number of hereditary human pathologies. With age, the incidence of diseases increases. In childhood, the percentage of patients is at least 10%, and in the elderly - 25-30%.
The distribution of multifactorial diseases in different human populations can vary significantly, which is associated with differences in genetic and environmental factors. As a result of genetic processes occurring in human populations, selection, mutation, migration, genetic drift, the frequency of genes that determine hereditary predisposition can increase or decrease until they are completely eliminated.
Features of polygenic diseases
The clinical picture and severity of multifactorial human diseases are very different depending on gender and age. At the same time, with all their diversity, the following common features are distinguished:
High incidence of diseases in the population. Thus, about 1% of the population suffers from schizophrenia, 5% from diabetes, more than 10% from allergic diseases, and about 30% from hypertension.
Clinical polymorphism of diseases varies from hidden subclinical forms to pronounced manifestations.
Features of inheritance of diseases do not correspond to Mendelian patterns.
The degree of manifestation of the disease depends on the gender and age of the patient, the intensity of his endocrine system, unfavorable factors of the external and internal environment, for example, poor nutrition, etc.
Genetic prediction of polygenic diseases
Genetic prognosis for multifactorial diseases depends on the following factors:
the lower the frequency of the disease in the population, the higher the risk for the proband’s relatives

the stronger the severity of the disease in the proband, the greater the risk of developing the disease in his relatives

the risk to relatives of the proband depends on the degree of relatedness to the affected family member

the risk for relatives will be higher if the proband belongs to the less affected sex.
The polygenic nature of diseases with hereditary predisposition is confirmed using genealogical, twin and population statistical methods. The twin method is quite objective and sensitive. Using the twin method, a hereditary predisposition to certain infectious diseases - tuberculosis, polio and many common diseases - coronary heart disease, rheumatoid arthritis, diabetes mellitus, peptic ulcer, schizophrenia, etc. is shown.

Gene diseases are groups of diseases that are heterogeneous in clinical manifestations and arise under the influence of mutations at the gene level. Separately, we should consider a group of diseases that arise and develop against the background of a defect in the hereditary apparatus of cells and the influence of unfavorable environmental factors.

What are multifactorial hereditary diseases?

This particular group of diseases has one clear difference from gene diseases. Multifactorial diseases begin to manifest themselves in unfavorable environments. Some scientists have suggested that genetic predisposition may never manifest itself unless environmental factors arise.

The etiology and genetics of multifactorial diseases is very complex; the origin has a multi-stage structure and can be different in the case of each specific disease.

Types of multifactorial pathologies

Conditionally multifactorial can be divided into:

  • native developmental defects;
  • mental and nervous diseases;
  • age-related diseases.

Depending on the number of genes involved in the pathology, there are:

  • Monogenic diseases - have one mutant gene, which creates a person’s predisposition to a particular disease. In order for the disease to begin to develop in this case, exposure to one specific environmental factor will be necessary. This may be physical, chemical, biological or medicinal effects. If a specific factor has not arisen, even if there is a mutant gene, the disease will not develop. If a person does not have a pathogenic gene, but is exposed to external environmental factors, the disease will also not occur.
  • Polygenic hereditary diseases or multifactorial diseases are determined by pathologies in many genes. The action of multifactorial signs can be discontinuous or continuous. But any disease can arise only through the interaction of many pathogenic genes and environmental factors. Normal human characteristics, such as intelligence, height, weight, skin color, are continuous multifactorial characteristics. Isolated (cleft lips and palate), congenital heart disease, neural tube defects, polyrostenosis, hypertension, peptic ulcer and some others have a higher incidence in close relatives than in the general population. Multifactorial diseases, examples of which are mentioned above, are “intermittent” multifactorial symptoms.

Diagnosis of MFZ

Various types of studies help diagnose multifactorial diseases and the role of genetic inheritance. For example, a family study, thanks to which the concept of “oncological family” appeared in the practice of doctors, that is, a situation when within the same pedigree there are repeated cases of malignant diseases in relatives.

Doctors often resort to studying twins. This method, like no other, allows you to operate with reliable data on the hereditary nature of the disease.

When studying multifactorial diseases, scientists pay a lot of attention to studying the connections between the disease and the genetic system, as well as to analyzing the pedigree.

Criteria characteristic of MFZ

  • The degree of relationship directly affects the likelihood of the disease occurring in relatives, that is, the closer the relative is to the patient (genetically), the greater the likelihood of the disease occurring.
  • The number of patients in the family affects the risk of the disease in the patient’s relatives.
  • The severity of the disease in the affected relative influences the genetic prognosis.

Diseases related to multifactorial

Multifactorial diseases include:

Bronchial asthma is a disease based on chronic allergic inflammation of the bronchi. It is accompanied by hyperactivity of the lungs and periodic occurrence of attacks of difficulty breathing or suffocation.

Peptic ulcer, which is a chronic recurrent disease. It is characterized by the formation of ulcers in the stomach and duodenum due to disturbances in the general and local mechanisms of the nervous and humoral systems.

Diabetes mellitus, the occurrence of which involves both internal and external factors that cause disturbances in carbohydrate metabolism. The occurrence of the disease is greatly influenced by stress factors, infections, injuries, and operations. Risk factors may include viral infections, toxic substances, excess body weight, atherosclerosis, and decreased physical activity.

Heart failure is a consequence of a reduced or complete lack of blood supply to the myocardium. This happens due to pathological processes in the coronary vessels.

Prevention of multifactorial diseases

Types of prophylaxis that prevent the occurrence and development of hereditary and congenital diseases can be primary, secondary and tertiary.

The primary type of prevention is aimed at preventing the conception of a sick child. This can be realized in planning childbirth and improving the human environment.

Secondary prevention is aimed at terminating pregnancy if the likelihood of the disease in the fetus is high or the diagnosis has already been established prenatally. The basis for making such a decision may be a hereditary disease. Occurs only with the consent of the woman within the established time frame.

The tertiary type of prevention of hereditary diseases is aimed at combating the development of the disease in an already born child and its severe manifestations. This type of prevention is also called norm copying. What it is? This is the development of a healthy child with a pathogenic genotype. Norm copying with the appropriate treatment complex can be done in utero or after birth.

Prevention and its organizational forms

Prevention of hereditary diseases is implemented in the following organizational forms:

1. Medical genetic counseling is specialized medical care. Today, one of the main types of prevention of hereditary and genetic diseases. For medical genetic consultation please contact:

  • healthy parents who gave birth to a sick child, where one of the spouses has the disease;
  • families with practically healthy children, but who have relatives with hereditary diseases;
  • parents seeking to make a prognosis for the health of brothers or sisters of a sick child;
  • pregnant women who have an increased risk of having a child with abnormal health.

2. Prenatal diagnosis is the prenatal determination of congenital or hereditary pathology of the fetus. In general, all pregnant women should undergo examination to exclude hereditary pathologies. For this purpose, ultrasound examination and biochemical studies of pregnant serum are used. Indications for prenatal diagnosis may include:

  • the presence of an accurately diagnosed hereditary disease in the family;
  • mother's age exceeding 35 years;
  • previous spontaneous abortions in a woman, stillbirths with unclear causes.

The importance of prevention

Every year it improves and provides more and more opportunities to prevent most hereditary diseases. Each family with health problems is given full information about what they risk and what they can expect. By increasing the genetic and biological awareness of the general population, promoting a healthy lifestyle at all stages of a person's life, we increase humanity's chances of having healthy offspring.

But at the same time, polluted water, air, and mutagenic food products increase the prevalence of multifactorial diseases. If the achievements of genetics are applied in practical medicine, then the number of children born with hereditary genetic diseases will be reduced, early diagnosis and adequate treatment of patients will be available.

Related publications