Medical genetic counseling presentation. Presentation of the practical lesson "Medical genetic counseling. Prevention of hereditary pathology." Methodological approaches to prenatal diagnosis

Practical lesson

(2 hours)

Teacher

Smirnova Z. M.

According to world statistics, annually among 4-5% of newborns there are significant

hereditary defects.

In this connection, the diagnosis of hereditary diseases, assessment of the risk of developing this disease, as well as methods for their prevention are of particular importance.

Currently main warning method of hereditary diseases consists of medical and genetic counseling of families burdened with hereditary pathology.

The main goal of genetic counseling is preventing the birth of a sick child.

The practical lesson is aimed at studying the stages of MGC, using and systematizing all the knowledge acquired while studying the discipline

the student must know:

Main groups of hereditary diseases, causes and mechanisms of their occurrence

2. Indications for referral to medical

genetic counseling;

counseling methodology

(MGC STAGES);

The student must be able to:

Conduct preliminary diagnostics hereditary diseases;
Calculate the risk of giving birth to a patient child;
Develop recommendations for families couples to prevent birth children with hereditary pathology.

Basic terms and concepts

DEFINITION

– specialized type of medical care to the population aimed at preventing hereditary diseases

Medical genetic counseling

– determining the degree of genetic risk in the family being examined and assisting the family in making the right decision on family planning issues

Purpose of genetic consultation

Determining the health prognosis for future offspring in families where there is a risk of hereditary pathology;
Assistance in making decisions about childbearing depending on the degree of risk;
Assistance in making a diagnosis of a hereditary disease;

Clinical observation and identification of high-risk groups among relatives.

Objectives of the MGK

Define the basic terms

The age of parents, especially women, is over 35 years old;
The presence of hereditary diseases in the family and among relatives;
Birth of defective children;
Consanguineous marriage;
Primary infertility of spouses;
Primary miscarriage;
Intolerance to drugs and products;
Primary amenorrhea, especially in combination with underdevelopment of secondary sexual characteristics.

Indications for referral to MGK

Diseases that arise as a result of changes in the hereditary apparatus (chromosomal and gene mutations) and which can be inherited

Hereditary diseases

– comprehensive diagnosis of a pregnant woman in order to identify malformations and congenital anomalies in the fetus at the prenatal stage

Prenatal diagnosis

Define the basic terms

Non-invasive – examination of a pregnant woman without damaging fetal tissue.

Invasive - with violation of the integrity of fetal tissues.

Invasive and non-invasive methods

the probability of an anomaly occurring in the patient (proband) or his relatives, which is expressed as a percentage (from 0 to 100%):

over 20% - high.

Genetic risk

I – diagnosis

II – forecasting

III – conclusion

IGC stages

reduction in the incidence of hereditary diseases, as well as infant mortality and changes in the behavior of spouses addressing issues of childbirth

Counseling effectiveness criterion

I stage – diagnostics

Clarifying the diagnosis of a hereditary disease

II stage – forecasting

III stage - conclusion

and reporting the results

family

I MGK stage

Purpose of the stage

Examination and clarification of the diagnosis of hereditary pathology

Ways to achieve the goal

Studying the patient’s phenotype in order to identify characteristic symptoms;
Compiling a family pedigree and identifying consanguineous marriages;

Cytogenetic, molecular genetic and biochemical and other studies;

Study of karyotypes of the patient and family members;

How are hereditary diseases classified?

Chromosomal diseases -

determined by chromosomal and genomic mutations

Monogenic diseases, caused by gene mutations

Diseases with hereditary predisposition

(multifactorial) -

are caused by the total (additive) effect of several gene mutations, each of which independently cannot cause the development of the disease. A prerequisite for the occurrence of such diseases is exposure to unfavorable environmental factors.

What are the characteristics of changes in the hereditary apparatus in monogenic diseases and what signs are observed in patients?

Before mutation

Enzyme

After mutation

Gene (DNA)

T–A

C – G

G – C

T–A

C – G

G – C

A – T

G – C

T–A

Sign

Gene (DNA)

T–A

C – G

G – C

T–A

C – G

G – C

A – T

G – C

T–A

Sign

RNA Enzyme

- dropping out

C – G

Monogenic diseases caused by gene mutations

Enzymopathies (enzymopathies) – defects of individual enzymes.

Violations :

- amino acid ;

- carbohydrate ;

- lipid ;

- mineral metabolism.

Dysplasia – tissue structure disorder

Syndromes multiple congenital malformations – different tissues and systems involved

What are the characteristics of changes in chromosomal diseases and what signs are usually observed?

Chromosomal diseases -

these are clinical conditions caused by a violation of the number or structure of chromosomes

Genital pathology

chromosomes:

Shereshevsky syndrome-

Turner;

Klinefelter syndrome

Autosome pathology:

Patau syndrome;

Edwards syndrome;

Down's disease, etc.

Syndrome – a stable combination of symptoms

What are the main methods of medical genetics used to diagnose hereditary pathologies?

Methods of medical genetics

Population-statistical –

Genealogical –

construction of pedigrees and analysis of the transmission of traits over generations

studying the structure of human populations, determining the frequency of occurrence of genotypes and genes in a population

Biochemical –

apply to identify hereditary metabolic diseases

Cytogenetic –

studying karyotype using microscopic

technology and determination of Barr bodies in the nuclei of somatic cells

Molecular genetic

(DNA diagnostics)

a large and diverse group of methods designed to detect damage in the structure of a DNA section (gene, chromosome section) up to deciphering the nucleotide sequence .

The methods are based on genetic engineering manipulations of DNA and RNA.
The initial stage of molecular genetic methods is obtaining DNA samples.
The source of genomic DNA is any nucleated cells (leukocytes, chorion, amniotic cells).

For what purpose is the genealogical method used?

The method of compiling pedigrees was proposed in 1876. F. Galton

Queen Victoria

England

Alice

Leopold

Beatrice

Frederick

William

Victoria-Evgenia

Alfonso Maurice XIII

Alice

Alexandra

Irena

Nicholas II

Trematan Alfonso

Alexei

Russia

Waldemar Henry

Inheritance of hemophilia in the royal houses of Europe

II MGK stage

Purpose of the stage

Risk calculation - determining the likelihood of a hereditary pathology occurring in a family

Way to achieve the goal

Genetic risk assessment, depending on the type of hereditary pathology:

Theoretical calculations (for monogenic diseases) based on genetic patterns;
Empirical data (multifactorial and chromosomal diseases)

What groups are counseling based on prognosis of offspring classified into?

Consultation on the prognosis of offspring is divided into:

prospective –

the risk of having a sick child is determined

even before pregnancy or in its early stages

retrospective –

after the birth of a sick child regarding the health of future children

What is genetic risk?

Genetic risk – the probability of manifestation of hereditary pathology in the patient himself (proband) or his relatives, which is expressed as a percentage (from 0 to 100%):

5% - regarded as low,
up to 10% - mildly elevated,
up to 20% - increased to a moderate degree and
over 20% - high.

How is the prognosis of offspring carried out in different forms of hereditary pathology?

The main methods for assessing genetic risk:

empirical data and theoretical calculations.

Theoretical calculations based on genetic patterns are used when

monogenic diseases

For chromosomal diseases - in the absence abnormalities in the karyotype of the parents, the likelihood birth of a second child with a chromosomal

the anomaly is estimated to be no more than 1%

For multifactorial diseases - empirical data on familial frequency

diseases

Example of an empirical risk table

Risk of illness for relatives of patients with various mental illnesses (in%)

Relatives of the patient

Schizophrenia

Siblings if both parents are healthy

Affective insanity

Siblings if one of the parents is sick

Epilepsy

Siblings if both parents are sick

Dizygotic twin

Monozygotic twin

III stage of the IGC

Purpose of the stage

Explanation in an accessible form of the degree of genetic risk of having offspring with hereditary pathology;
Help in making the right decisions regarding childbirth.

Ways to achieve goals

Explain the significance of various additional factors (the severity of the disease, the possibility of treatment and the essence of prenatal diagnosis);
The final decision on this issue remains with the family.

Who makes decisions about childbearing?

The final stage of counseling is communicating the results to the family.

Reported only for parents
So much time is allocated for conversation how much is needed
The decision to continue having children accept only parents

How is early diagnosis of hereditary diseases carried out?

Express methods and prenatal diagnostics (prenatal determination of pathology in the fetus)

Sifting (mass examination) Non-invasive methods: - Ultrasonic study (10-14; 19-22; 32-34 weeks) - Biochemical prenatal screening: - hCG, - estriol - alphafetoprotein (16 – 18 weeks)

Invasive methods (there is a risk of miscarriage):

Chorionic villus biopsy (10-14 weeks)
Placentocentesis and amniocentesis (from 14 to 20 weeks)
Cordocentesis - blood from fetal umbilical cord) (after 20 weeks)

At 11-14

weeks

The parents' decision may be:

Give birth to
Don't give birth
Adopt
Break up the marriage
Give birth to someone else partner
Apply donor insemination
Give birth, but with carrying out prenatal

diagnostics

The possibility of prenatal diagnosis is decisive for making a positive decision regarding the completion of pregnancy

Learning task 1

A 22-year-old woman, whose brother died at the age of 4, contacted MGK.

According to the woman, the patient had frequent bronchitis and pneumonia, with poor sputum discharge. Disorders of the digestive function of the pancreas and intestines: frequent abdominal pain, flatulence, fetid, fatty, putty-like feces. The child also had a delay in physical development.

Job 1

Based on the characteristic features, determine the most likely hereditary pathology. What methods of genetic research will be crucial in diagnosing this hereditary pathology? Justify your answer.

Work 2. Based on the given pedigree, determine the type of inheritance of cystic fibrosis.

Justify your answer.

Work 3. Record the karyotype of a patient with cystic fibrosis. Find a card with this karyotype.

II stage – forecasting

risk of having a sick child

Job 4

Determine the principle of genetic risk assessment (empirical or theoretical calculation) in the case of cystic fibrosis. Justify your answer.

Calculate the risk of having a sick child in this case.

Task 4. Genetic explanation

conclusion for the family – III stage of the MGC

Work 5.

Having determined the type of inheritance of cystic fibrosis, answer the questions that interest the young woman:

a) What is the probability that she the unborn child will appear

cystic fibrosis and does it depend on gender child?

Problem 2 As a result of a disorder of embryonic development associated with a neural tube defect, an increased level of α-fetoprotein is detected in the anatomical fluid (or in the blood of a pregnant woman). However, in approximately 40% of tests for α-fetoprotein content, an increased level of the latter is not accompanied by a defect in the development of the neural tube, but is explained by other reasons (other developmental anomalies, pregnancy complications, chronic diseases of the pregnant woman, etc.) and the fetus may be healthy .

A pregnant woman, in whose blood, as a result of testing, an increased level of α-fetoprotein was detected, wants to terminate the pregnancy, fearing that the fetus has a serious developmental pathology. What would be your recommendations?

Algorithm for an indicative basis of action

Patient

Drawing up a pedigree

Biochemical, cytogenetic, molecular genetic and other studies

Forecasting

Slide 1

Slide 2

- a branch of preventive medicine, the main goal of which is to reduce the number of genetically determined diseases and congenital malformations. The purpose of genetic consultation is to establish the degree of genetic risk in the examined family and explain to the spouses in an accessible form the medical genetic report.

Slide 3

What is medical genetic counseling? “... a communication process associated with solving problems regarding the occurrence or risk of genetic diseases in the family. This process involves an attempt by one or more qualified professionals to assist the patient or family in the following matters: understand the medical facts, including the diagnosis, possible course of the disease and available treatment evaluate the inheritance of the disease and the risk of its recurrence determine the possibility of making a decision based on the magnitude of the risk of recurrence choose a series of actions in accordance with this decision, taking into account risk and family goals to help those consulted better adapt to the disease and the risk of recurrence of this disease in the family ... "

Slide 4

Objectives of medical genetic counseling: retro- and prospective counseling of families and patients with hereditary or congenital pathologies; prenatal diagnosis of congenital and hereditary diseases; assistance to doctors of various specialties in diagnosing the disease, if this requires special genetic research methods; providing the patient and his family with information in an accessible form about the degree of risk of having sick children and assisting them in making decisions; maintaining a territorial register of families and patients with hereditary and congenital pathologies and their dispensary observation; Promotion of medical and genetic knowledge among the population.

Slide 5

In other words, the task of genetic consultation is to draw up a genetic prognosis in the family of an individual with an anomaly of physical, mental or sexual development and to select preventive measures to prevent the birth of a sick child.

Slide 6

Drawing up a genetic prognosis includes three stages: Stage 1. Determination of the degree of genetic risk. Genetic risk refers to the probability (from 0 to 100%) of a certain anomaly occurring in the patient (proband) or his relatives. The overall risk of a genetically determined anomaly for European populations is 3-5% (genetic load), so a risk that does not exceed 5% is regarded as low. A genetic risk of up to 10% is called mildly increased, up to 20% - moderately increased, and above 20% - high.

Slide 7

Genetic risk calculations There are two ways to calculate genetic risk: theoretical calculations based on genetic patterns, and empirical data. For Mendelian diseases, the theoretical basis for risk assessment comes down to the identification and probabilistic assessment of a specific discrete genotype underlying the disease. In complexly inherited diseases, there is no specific discrete genotype responsible for the development of the disease, so counseling is often based on pure empiricism, on the “black box” method.

Slide 8

Stage 2. Assessing the severity of the medical and social consequences of the suspected anomaly. The degree of genetic risk does not always correspond to the severity of the expected pathology. For example, polydactyly (an autosomal dominant type of inheritance, a high degree of genetic risk - at least 50%) can be easily eliminated by appropriate corrective surgery, and a person can lead a normal life, while phenylketonuria, the risk of which in children of heterozygous parents is 25% is a serious disease that is difficult to treat. In the second case, the degree of suffering from a medical point of view and social consequences for the patient and his family is regarded as severe.

Slide 9

Stage 3 - a geneticist must evaluate the prospects for the use and effectiveness of prenatal diagnostic methods. Advances in this area make it possible to plan childbearing in families with a high risk of inheriting severe pathologies (Down disease, mucopolysaccharidosis, hemophilia, cystic fibrosis, etc.), since these diseases can be detected by prenatal diagnostic methods.

Slide 10

Correct preparation of a medical genetic prognosis depends on the following factors: accuracy of diagnosis, adequacy of using methods for calculating genetic risk, familiarity with the latest literature data,

Slide 11

Indications for referring a family to medical genetic consultation: the presence of similar diseases in several family members; primary infertility of spouses; recurrent miscarriage; child's retardation in mental and physical development; the birth of a child with congenital malformations; primary amenorrhea, especially with underdevelopment of secondary sexual characteristics; consanguinity between spouses.

Slide 12

Slide 13

Slide 14

Slide 15

Slide 16

Levels of medical and genetic assistance to the population POPULATION OF THE INSTITUTION 150 million Federal centers: new methods of diagnosis (biochemical, cytogenetic, molecular genetic), counseling, prenatal diagnosis, treatment and rehabilitation 6 - 8 million Interregional medical and genetic consultations: counseling, cytogenetic and biochemical diagnostics, prenatal diagnostics (ultrasound, serum markers, invasive), screening for PKU and hypothyroidism 1.5 – 2 million. Medical genetic consultations: consultation, cytogenetic and biochemical diagnostics, prenatal diagnostics (ultrasound, serum markers) 50 – 60 thousand Geneticist of the Central District Hospital: selection of families with hereditary pathology and referral to the Moscow City Clinical Hospital

Slide 17

Moral and ethical problems When providing medical and genetic counseling, there are a number of difficulties of a moral and ethical nature: interference with family secrets (occurs when collecting data to construct pedigrees, when identifying carriers of a pathological gene, when passport and biological paternity do not match, etc.; the problem is resolved by correct attitude doctor to patient); responsibility of the geneticist in the case of advice to those consulting on the basis of a probabilistic prognosis (it is necessary that the patient correctly understands the medical-genetic information, the consultant should not give categorical advice (the final decision is made by the consultants themselves).

Slide 18

The task of MGC from a social point of view is to help the family make the right decision. The geneticist must help those consulting to understand the medical facts, the type of inheritance of the disease, the genetic risk of its recurrence in the family, to better adapt to misfortune and make the right decision regarding further childbearing. The effectiveness of MGC directly depends on the competent performance of this communicative function by the consulting physician.

Slide 19

Requirements for the image of a communicator (geneticist): A qualified doctor with experience in the syndromological approach to diagnosis A geneticist who knows the formal foundations and modern achievements of genetics A specialist who knows the basics of variation statistics A psychologist who can assess the personality structure, psychological status of patients and build a conversation on this basis A teacher who can explain in an accessible form the meaning of a genetic conclusion

Slide 20

Prenatal (prenatal) diagnosis of hereditary diseases - provides for their timely detection. Thus, prenatal diagnosis is associated with solving a number of biological and ethical problems before the birth of a child, since this is not about curing a disease, but about preventing the birth of a child with a pathology that cannot be treated. Prenatal diagnostics allows us to move from probabilistic to unambiguous prediction of pregnancy outcome.

Slide 21

General indications for prenatal diagnosis Increased genetic risk of having a child with a hereditary or congenital disease. Severe nature of the disease, justifying termination of pregnancy Lack of a satisfactory method of treating the suspected disease Availability of an accurate diagnostic test Family consent to prenatal diagnosis and termination of pregnancy if indicated

Slide 22

Methodological approaches to prenatal diagnosis Requirements for methods: High accuracy of the method Low risk of complications Short gestational age Minimum period for obtaining results

Slide 23

Methods of prenatal diagnosis Currently, indirect and direct methods of prenatal diagnosis are used. With indirect methods, the pregnant woman is examined (obstetric and gynecological methods, blood serum for alpha-fetoprotein, etc.); with straight lines - fruit. Direct non-invasive (without surgical intervention) methods include ultrasonography; to direct invasive (with violation of tissue integrity) - fetoscopy, chorionic biopsy, placentobiopsy, amniocentesis, cordocentesis.

Slide 24

Indirect methods The most widely used triad of methods is the study of the level of alpha-fetoprotein (AFP), the content of human chorionic gonadotropin (HCG) and free estriol in the blood of women in the 2nd trimester of pregnancy. The content of alpha-fetoprotein is also determined in the amniotic fluid, and free estriol is determined in the urine of pregnant women. Deviations in the plasma levels of AFP, hCG, and free estriol in a pregnant woman serve as indicators of high risk for the fetus.

Slide 25

Indirect methods In particular, the content of alpha-fetoprotein in biological fluids is increased in cases of multiple malformations, spina bifida, hydrocephalus, anencephaly, malformations of the gastrointestinal tract and other defects. In cases of chromosomal diseases in the fetus (for example, Down's disease) or the presence of type I diabetes mellitus in a pregnant woman, on the contrary, the concentration of alpha-fetoprotein in the blood of pregnant women is reduced.

Slide 26

Indirect methods Chorionic gonadotropin, synthesized by the trophoblast of the placenta, is determined already on the 8-9th days after conception. When examining a woman’s blood in the 2nd trimester of pregnancy, an increase in the level of hCG and its free beta subunits indicates a delay in intrauterine development of the fetus and a high risk of its antenatal death. The content of free estriol in the biological fluids of a pregnant woman reflects fetoplacental activity and decreases with fetal pathology and dysfunction of the placenta. Ultrasonography (echography) is the use of ultrasound to obtain an image of the fetus and its membranes, the condition of the placenta. Starting from the 5th week of pregnancy, you can get an image of the membranes of the embryo, and from the 7th week - of the embryo itself. At the 12-20th week of pregnancy, it is already possible to localize the placenta, diagnose twin pregnancy, anencephaly, defects of the skeletal system and closure of the neural tube, and atresia of the gastrointestinal tract.

Slide 29

Ultrasonography (echography) Ultrasound examination allows you to obtain data on the size of the fetus (length of the body, hip, shoulder, head diameter), myocardial function, the volume of amniotic fluid and the size of the placenta. Ultrasound can detect a number of developmental anomalies in the fetus - anencephaly, hydrocephalus, polycystic kidney disease or agenesis, limb dysplasia, pulmonary hypoplasia, multiple congenital defects, heart defects, hydrops (edema) of the fetus and placenta. About 70% of all fetal conditions are detected, accompanied by congenital malformations, both isolated and as part of chromosomal and hereditary syndromes.

Slide 30

Amniocentesis is the collection of amniotic fluid and fetal cells, carried out under ultrasound guidance, for subsequent analysis. Obtaining the test material (cells and fluid) is possible at the 16th week of pregnancy. Amniotic fluid is used for biochemical studies (gene mutations are detected), and cells are used for DNA analysis (gene mutations are detected), cytogenetic analysis. Possible complications (1%-1.5%): injury to the fetus, placenta, large vessels; infection of the uterine cavity; bleeding; miscarriages. (from R.Lewis, 1994) 32

Cordocentesis Optimal timing: 16 – 20 weeks of pregnancy Obstetric approaches: umbilical cord puncture. Possible complications are minimal (infection, miscarriages). Range of diagnostic capabilities: same as for amniocentesis.

Slide 33

Modern technologies, in addition to the methods listed above, allow biopsy of the skin, muscles, and liver of the fetus to diagnose many hereditary diseases. The risk of miscarriage when using invasive prenatal diagnostic methods is 1-2%. Further development and dissemination of methods for prenatal diagnosis of hereditary diseases will significantly reduce the incidence of hereditary pathology in newborns. Presentation on genetics
on the topic: "Medicogenetic
consulting"
Group 1 SD-1
Petrova N., Savluk T.
Teacher:
Sergeeva L.V.:

Medical genetic counseling, MGK

1. The main goal of the IGC
2. Objectives and organization
3. Population,
subject to referral to
MGK
4. Basic principles
counseling
(promising,
retrospective)
5. Stages of consultation.

"We used to
thought it was ours
determine fate
stars. Now we
we know that ours
destiny is ours
genes"
Nobel laureate James Watson

1. The main goal of the IGC

Preventing the birth of children with
incurable congenital diseases;
In a general population sense, there is a decrease
the burden of pathological heredity;
The purpose of a separate consultation is to help the family in
making the right decisions on issues
family planning.

MINISTRY OF HEALTH AND SOCIAL DEVELOPMENT OF THE RUSSIAN FEDERATION ORDER of March 22, 2006 N 185 ON MASS INSPECTION OF NEWBORN BABIES

MINISTRY OF HEALTH AND SOCIAL DEVELOPMENT
RUSSIAN FEDERATION
ORDER
dated March 22, 2006 N 185
ABOUT MASS SCREENING OF NEWBORN CHILDREN FOR HEREDITARY DISTRIBUTIONS
DISEASES
In order to conduct mass screening of newborn children for hereditary diseases, I order:
1. Approve:
Regulations on the organization of mass examination of newborn children for hereditary
diseases according to Appendix No. 1;
Recommendations for collecting blood samples during mass screening of newborns
hereditary diseases according to Appendix No. 2.
2. Department of medical and social problems of family, motherhood and childhood (O.V. Sharapova) until July 1
2006, develop regulations on the organization of quality control during mass surveys
newborn children for hereditary diseases.
3. Recommend to the heads of healthcare authorities of the constituent entities of the Russian Federation
provide:
- conducting mass examination of newborn children for hereditary diseases in accordance with
Regulations and Recommendations approved by this Order;
- streamlining the structure of the medical genetic service in connection with the expansion of tasks for conducting mass
examination of newborn children for hereditary diseases and taking into account the increase in the volume of work;
- equipping medical genetic consultations (centers) with the necessary equipment and consumables
materials for laboratory testing of blood samples;
- conducting molecular genetic and clinical studies in existing or newly created
molecular genetic laboratories, medical genetic consultations (centers) or laboratories
(departments) of federal specialized medical institutions, federal state
institutions of higher education;
- coordination of the stages of mass examination of newborn children for hereditary diseases;
- information support for mass screening of newborn children for hereditary diseases.
4. Control over the implementation of this Order is entrusted to the Deputy Minister of Health and
social development of the Russian Federation V.I. Starodubova.
Minister
M. ZURABOV

Appendix No. 1 to the Order of the Ministry of Health of the Kaliningrad Region dated April 1, 2011 No. 76 ORDER for prenatal

Appendix No. 1
to the Order
Ministry of Health
Kaliningrad region
dated April 1, 2011 N 76
ORDER
carrying out prenatal (antenatal) diagnosis of disorders
child development in state and municipal
healthcare institutions of the Kaliningrad region
All pregnant women registered at the dispensary
in municipal and state antenatal clinics
healthcare institutions of the Kaliningrad region in the first
trimester, are subject to mandatory referral to the regional office
prenatal diagnostics medical-genetic consultation center
Family Planning and Reproduction State Agrarian University of the Kaliningrad Region
"Regional Perinatal Center" for
centralized biochemical and ultrasound screening in
in order to identify child developmental disorders (congenital and
hereditary pathology in the fetus at 11-14 weeks of pregnancy).

2. Objectives and organization

The tasks of medical genetic
counseling are:
1) retro- and prospective consulting
families and patients with hereditary or
congenital pathology;
2) prenatal diagnosis of congenital and
hereditary diseases
ultrasound, cytogenetic,
biochemical and molecular genetic methods;
3) assistance to doctors of various
specialties in diagnosing us
glacial or congenital disease,
if this requires special
genetic research methods
4) explanation to the patient and his family in
in an accessible form about the magnitude of the risk of having
sick offspring and providing them with assistance in
making a decision;
5) maintaining a territorial register of families
and patients with congenital and congenital
pathology and their dispensary observation;
6) promotion of medical genetic knowledge
among the population.

3. Population subject to referral to the MGK

The birth of a child with congenital
developmental, mental and
physical retardation, blindness and
deafness, seizures, etc.
Spontaneous abortions, miscarriages,
stillbirths.
Consanguineous marriages.
Unfavorable course
pregnancy.
Spouses working in harmful jobs
enterprise.
Incompatibility of married couples
Rh factor of blood.
The woman is under 18 and
over 35 years old, and men - 40 years old.
Irradiation
Presence of similar diseases in
several family members
Primary infertility of spouses
Primary amenorrhea, especially with
underdevelopment of secondary reproductive organs
signs.

Assessment of various aggravating factors

Aggravating factors
points
Age 36-40 years
2
Age over 40 years
4
Compensated rheumatic heart defects
2
Inflammatory diseases of the uterus and appendages, uterine fibroids, cyst
ovary
2
Spontaneous abortion
2(for each)
Birth of a child with developmental defects
4
Consanguineous marriage
3
Threat of miscarriage before 10 weeks of pregnancy
1
Multiple threats of miscarriage that began before 10 weeks
3
Miscarriage before 35 weeks
4
Miscarriage 36-37 weeks
2
Post-maturity
2
7Polyhydramnios
7
Low water
3
Breech presentation
3

Population groups applying to the MGK.

Population groups
Target
appeals
Percentage of families
Healthy spouses
having a patient
child
Forecast
offspring
65
Persons with
hereditary
pathology
Clarification
diagnosis
30
Healthy faces
having sick
relatives
Forecast
health and
offspring
5

Structure of appeals to MGK

Type of inheritance and pathology groups
Percentage of families
Autosomal dominant
9
Autosomal recessive
16.5
X-linked
2
Chromosomal diseases
20
Multifactorial diseases
40
With unspecified inheritance type
12.5

Main pathology groups in MGC

Pathology groups
Percentage of families
Congenital malformations
30.6
Neuropsychiatric diseases and syndromes
27.8
Miscarriage and infertility
18.2
Others
15.4

Levels of medical and genetic assistance to the population

Number
population
Institutions
150 million
Federal centers: new diagnostic methods
(biochemical, cytogenetic, molecular genetic) counseling, prenatal
diagnostics, treatment and rehabilitation
6-8 million
Interregional medical and genetic consultations:
consultation, biochemical and cytogenetic
diagnostics, prenatal diagnostics (ultrasound,
serum markers, invasive diagnostics)
screening for PKU hypothyroidism.
1.5-2 million
Medical genetic consultations: consultation,
biochemical and cytogenetic diagnostics,
prenatal diagnostics (ultrasound, serum
markers)
50-60 thousand
Geneticist of the Central District Hospital: selection of families with hereditary
pathology and referring them to the MGK.

4. Basic principles of counseling (prospective, retrospective)

Prospective
consulting
carried out before conception
and/or before birth
child; meaning -
probability forecast and
risk assessment
birth of children with
hereditary
pathology in couples
parents first of all
from risk groups.
Retrospective
consulting
carried out in case
births in the family
sick child (there is
proband); meaning -
probability forecast and
risk assessment
birth of patients
children in this family
perspective.

Scheme of the medical genetic service and its connections with practical medicine

5. Consulting stages

Medical genetic consultation includes 4 stages:
Stage 1 - diagnosis.
The first stage starts with
clarifying the diagnosis
hereditary
diseases. Depending
on the accuracy of the diagnosis
There are 3 groups of people:
1) who have
suspicions of
hereditary disease;
2) with installed
diagnosis, however, he
raises doubts;
3) with the correct
diagnosis.

Stage 2 - forecast.

The second stage is aimed at
definition of prognosis
offspring. In this case it is decided
genetic problem or
method applied
antenatal diagnostics.
Genetic risk
determined in two ways:
1) through theoretical
genetic calculations
patterns;
2) using empirical
data for diseases with
by an unclear mechanism.

Stage 3 – conclusion

After diagnosis
proband, examinations
relatives and decisions
genetic problem
determination of genetic risk,
a conclusion is drawn up. Accepted
consider the genetic risk to be up to 5%
low, up to 20% - medium and higher
20% - high. Genetic risk
medium degree is regarded as
contraindication to conception or
termination of pregnancy. At
explaining genetic risk in
in each case must be indicated
general population frequency
birth of children with anomalies,
component of at least 4-5%.
Treatable diseases are not
are a contraindication to
childbirth (color abnormalities
vision, atherosclerosis). Recommendations about childbirth
are of great importance:
1. for lethal
diseases;
2. for intractable
treatment of autosomal and
interlocked with the floor
dominant and recessive
diseases;
3. with chromosomal
diseases;
4. for mental
diseases;
5. consanguineous
marriages

Moral and ethical issues

In medical genetic counseling, there are a number of
difficulties of a moral and ethical nature:
interference with family secrets (occurs when collecting data for
constructing pedigrees when identifying carriers of pathological
gene, if passport and biological paternity do not match, etc.;
the problem is resolved by the correct attitude of the doctor towards the patient);
responsibility of a geneticist in the case of advice to those consulting on
based on a probabilistic prognosis (it is necessary that the patient
understood the medical genetic information correctly, the consultant did not
must give categorical advice (final decision
accepted by the consultees themselves).

“Chromosomal diseases” - Mendel’s 2nd law – the law of segregation. Chromosomal. Diagram of Mendel's first and second laws. Checked by teacher: Kalentyeva N.V. Semey, 2012 Progeria. Monogenic. Ichthyosis. Polygenic. Conditions for the implementation of Mendel's laws.

“Genetics and hereditary human diseases” - Recessive? Among Asians, people with the third blood group predominate. Every year, 90 thousand mentally retarded children are born around the world. The occurrence of blood groups varies in different human populations. 3. Autosomal recessive inheritance Albinism Phenylketonuria Sickle cell anemia. How are human genetics studied?

“Human Genetic Diseases” - G. Heine Our doctors must know the laws of heredity like ABC. Tests to determine color blindness. Children with PKU are born without any signs of the disease. Colorblindness. Chromosome 21 appears not in double, but in triple quantity (trisomy). Klinefelter's syndrome. For parents after 40 years of age, the incidence of sick children increases sharply.

“Celiac disease” - Hereditary diseases of the gastrointestinal tract - Celiac disease, congenital diarrhea. Total disruption of membrane digestion and absorption. Diagnostics. The purpose of vitamins is primarily fat-soluble, preferably in easily digestible (water-soluble) forms. Repeated histological and serological studies.

“Hereditary syndromes and diseases” - http://l.foto.radikal.ru/0612/08e0016d1d34.jpg. Chromosomal diseases. The probability of developing the disease in the offspring is 50%. http://images.yandex.ru/yandpage?&q=1900511643&p=0&ag=ih&text=%E8%F5%F2%E8%EE%E7%20%ED%E5%20%F1%F6%E5%EF%EB %E5%ED%ED%FB%E9%20%F1%20%EF%EE%EB%EE%EC&rpt=simage.

"Down's disease" - Limitation of ideas, distractions and generalizations. There are also disorders of the visual analyzer such as astigmatism and strabismus. Violation clinic. Problems with analyzers. The concept of "Down syndrome". Domestic - Lurie, Zabramnaya. Teaching children with Down syndrome. The birth rate of children with Down syndrome is approximately 1 in 600-800 newborns.

There are 30 presentations in total

Human genetics with the basics of medical genetics: textbook. for student institutions of secondary vocational educational institutions/ V.N.Gorbunova. - M.: Publishing center "Academy", 2012 pp. Medical genetics: a textbook for medical colleges / Ed. N.P. Bochkova. - M.:GEOTAR-Media, 2008 pp., HOMEWORK Lecture materials 9. For independent work (according to Gorbunov) Take notes: Glossary of terms p.230

Medical genetic counseling is a specialized type of medical care to the population aimed at preventing hereditary diseases. The purpose of medical genetic counseling to prevent the birth of children with incurable congenital diseases in the general population sense is to reduce the burden of pathological heredity, and the purpose of a separate consultation is to help the family make the right decision on family planning issues

Prospective counseling - counseling before pregnancy or in its early stages. Retrospective counseling is carried out after the birth of a sick child (congenital malformations, delayed physical development and mental retardation) regarding the health of future children.

Screening of newborns Congenital hypothyroidism is a disorder of the structure of the thyroid gland and defects in the biosynthesis of the hormones of this gland. Phenylketonuria is a genetic disease associated with a deficiency or absence of an enzyme that is necessary for the digestion of phenylalanine into torosine. Cystic fibrosis is a severe hereditary disease accompanied by an increase in the viscosity of gland secretions Adrenogenital syndrome - this disease is caused by the absence of one of the enzymes responsible for the synthesis of cortisol Galactosemia - a metabolic disorder, there is no enzyme that converts galactose into glucose. On the 4th-5th day, blood is taken from the child

Medical genetic counseling is recommended primarily for: Women over 35 years of age; Families where there have already been cases of the birth of children with congenital defects; Women who have had miscarriages, especially in the early stages (up to 12 weeks); Women with endocrine disorders; Families living in environmentally unfavorable areas that have contact with chemical and radiation mutagens; Pregnant women with abnormalities identified during ultrasound and biochemical examination.

Stages of medical genetic counseling 1. Diagnostics Consultation always begins with clarifying the diagnosis of a hereditary disease, since an accurate diagnosis is a necessary prerequisite for any consultation. Clarification of the diagnosis in medical genetic consultation is carried out using genetic analysis. In all cases, without exception, the genealogical research method is used. 2. Prediction Genetic risk can be determined either by theoretical calculations using methods of genetic analysis and variation statistics, or using empirical data 3. Conclusion. To achieve the goal of counseling, when talking with patients, one should take into account their level of education, socio-economic status of the family, personality structure and family relationships. The interpretation of risk must be tailored to each case individually.

Prenatal diagnosis of hereditary diseases is a complex, rapidly developing field of medicine using ultrasound diagnostics, surgical techniques and laboratory methods. Perinatal diagnostic methods can be divided into three groups: - screening, - non-invasive, - invasive (followed by laboratory diagnostics).

Characteristics of the main types of population genetic screening programs (based on WHO materials) Type of screening program Primary goal Secondary goal Preconceptional Reduction of risks to fetal health Informed choice for childbearing Prenatal Identification of couples at risk of having a sick child and affected fetuses during the period of possible abortion Diagnosis of an affected fetus ; prenatal or neonatal treatment Neonatal Identification of patients for early treatment Disease incidence data General population Identification of high-risk factors Prevention, early diagnosis and treatment of common diseases

Sifting laboratory methods include the determination of substances in the blood serum of a pregnant woman, called serum markers of matter, fetoprotein - a protein produced by the fetal liver in the prenatal period, its content changes during pregnancy, human chorionic gonadotropin, unbound estriol and some other substances

Recommended methods and tests during pregnancy Length of pregnancy (weeks) Methods and tests First visit (as early as possible) Determination of hemoglobin and hematocrit in the blood. General urine test, screening for urinary tract infections. Determination of blood type and Rh phenotype, titer of anti-HBs antibodies in Rh-negative women. Titer of anti-rubella antibodies Wasserman reaction Cytology of cervical smear Determination of HBs antigen in the blood Ultrasound examination of the fetus and placenta Amniocentesis or chorionic villus biopsy according to indications Level of -fetoprotein, as well as chorionic gonadotropin and free estriol in the blood Screening for diabetes mellitus, repeated determination of hemoglobin and blood hematocrit, urine test for protein, sugar, non-stress test 28th Repeated study of the titer of anti-RH antibodies in Rh-negative pregnant women, prophylactic administration of anti-RH (0) immunoglobulin, ultrasound of the fetus, determination of hemoglobin, blood hematocrit, bacteriological examination of vaginal smear

Non-invasive methods are methods of examining the fetus without surgical intervention. Currently, these include only ultrasound examination. For medical reasons, 3D ultrasound can be performed starting in weeks.

Amniocentesis is a test that is performed by puncturing the abdominal wall, uterus and bladder with a thin needle to take a sample of amniotic fluid. Genetic amniocentesis is a study of the fetal chromosome makeup and is usually performed between the 15th and 20th weeks.

Chorion and placentobiopsy Chorion and placentobiopsy have been used since the late 80s. These methods are used to obtain small amounts of chorionic villi or pieces of placenta during the 8th to 16th week of pregnancy. There is no fundamental difference between the indications for the use of these two biopsy methods. Cordocentesis Cordocentesis - taking blood from the umbilical cord is carried out from the 20th week of pregnancy. The procedure is carried out under ultrasound control. Blood samples are the subject of cytogenetic (lymphocytes are cultured), molecular genetic and biochemical methods for diagnosing hereditary diseases. In this case, it is possible... Fetal tissue biopsy Fetal tissue biopsy as a diagnostic procedure is carried out in the second trimester of pregnancy under ultrasound guidance. To diagnose severe skin lesions (ichthyosis, epidermolysis), a biopsy of the fetal skin is performed, followed by a pathomorphological examination. A fetal muscle biopsy is performed for diagnosis.

Fetoscopy Fetoscopy (insertion of a probe and examination of the fetus) does not present any great difficulties with modern flexible optical technology. However, the method of visual examination of the fetus to detect congenital malformations is used only for special indications. It is carried out in the 1st week of pregnancy.

According to the degree of threat (risk) of recurrence of hereditary diseases in a family, they are divided into 3 groups: 1. diseases with a high degree of genetic risk (1: 4), which include diseases with an autosomal dominant, autosomal recessive and sex-linked type of inheritance ; 2. diseases with a moderate degree of genetic risk (less than 1: 10); These include hereditary diseases caused by fresh mutations, as well as chromosomal diseases and diseases with a polygenic type of inheritance, i.e. a significant proportion of congenital deformities and hereditary diseases developing against a genetically unfavorable background; 3. diseases characterized by an insignificant risk of recurrence or complete absence of risk.