Genetic diseases are some of the most common diseases. Congenital malformations of the fetus, hereditary diseases in newborns Genomic pathology

List of genetic diseases * Main articles: hereditary diseases, hereditary metabolic diseases, fermentopathy. * In most cases, a code indicating the type of mutation and associated chromosomes is also given. also ... ... Wikipedia

Below is a list of symbolic ribbons (a symbolic, or notification ribbon, from the English. Awareness ribbon) a small piece of ribbon folded into a loop; used to demonstrate the attitude of the tape carrier to any issue or ... ... Wikipedia

This page is a glossary. See also: List of genetic malformations and diseases Genetics terms in alphabetical order ... Wikipedia

A service list of articles created to coordinate work on the development of the topic. This warning did not install ... Wikipedia

A section of human genetics devoted to the study of the role of hereditary factors in human pathology at all major levels of life organization from population to molecular genetic. The main section of M.g. constitutes clinical genetics, ... ... Medical Encyclopedia

Hereditary diseases - diseases, the occurrence and development of which is associated with defects in the software apparatus of cells, inherited through gametes. The term is used in relation to polyetiological diseases, in contrast ... Wikipedia

Diseases, the occurrence and development of which is associated with defects in the software apparatus of cells, inherited through gametes. The term is used in relation to polyetiological diseases, in contrast to the narrower group Genetic ... ... Wikipedia

Hereditary disease diseases, the occurrence and development of which is associated with defects in the software apparatus of cells, inherited through gametes. The term is used in relation to polyetiological diseases, in contrast to ... ... Wikipedia

Hereditary metabolic disorders include a large group of hereditary diseases affecting metabolic disorders. Such disorders make up a significant part of the group of metabolic disorders (metabolic diseases). ... ... Wikipedia

Books

• Children's diseases, Belopolsky Yuri Arkadyevich. The health of a child of any age is a special task for a doctor, because a growing organism requires more attention and greater vigilance in relation to diseases. Planned medical examinations, identification ...
• Introduction to molecular diagnostics and gene therapy of hereditary diseases, V. N. Gorbunova, V. S. Baranov. The book outlines modern ideas about the structure of the human genome, methods for studying it, studying genes whose mutations lead to severe hereditary pathology:…

Instruction

Today, several thousand genetic diseases are known to be caused by abnormalities in human DNA. Each of us has 6-8 damaged genes, but they do not manifest themselves and do not lead to the development of the disease. If a child inherits two similar abnormal genes from his father and mother, he will get sick. Therefore, future parents try to get an appointment with a geneticist in order to establish a possible risk of a genetic anomaly with his help.

Down syndrome is one of the most common genetic diseases. Babies with one extra chromosome are born with an altered facial structure, reduced muscle tone, and malformations of the digestive and cardiovascular systems. Such children lag behind their peers in development. The syndrome is registered in one child out of 1000 newborns and you can find out about it already in the second trimester of pregnancy, having passed prenatal screening.

Cystic fibrosis is most common in people from the Caucasus and. If both parents are carriers of defective genes, the risk of having a baby with impaired function of the respiratory system, reproductive system and digestive tract increases. The cause of these problems is the deficiency of protein, which is vital for the body, as it controls the balance of chlorides in the cells.

Hemophilia is a disease associated with increased bleeding. This disease is inherited through the female line and affects mainly male children. As a result of damage to the genes responsible for blood clotting, hemorrhages occur in the joints, muscles and internal organs, which can lead to their deformation. If such a baby has appeared in your family, you should know that he should not be given drugs that reduce blood clotting.

Fragile X syndrome, also known as Martin-Bell syndrome, is the most common type of congenital mental retardation. There are both minor and severe developmental delays. Often the consequences of this disease are associated with autism. The course of the disease determines the number of abnormal repeating sections in the X chromosome: the more there are, the more severe the consequences of the syndrome.

Turner syndrome can only occur in your child if you are carrying a girl. One in 3,000 newborns has a partial or complete absence of one or two X chromosomes. Babies with this disease have very small stature and non-functioning ovaries. And if a female child is born with three X chromosomes, a diagnosis of trisomy X syndrome is made, which causes mild mental retardation and, in some cases, infertility.

Each of us, thinking about a child, dreams of having only a healthy and ultimately happy son or daughter. Sometimes our dreams are wrecked, and a child is born seriously ill, but this does not mean at all that this own, native, blood (scientifically: biological) child will be less loved and less dear in most cases.

Of course, at the birth of a sick child, there are immeasurably more worries, material costs, physical and moral burdens than at the birth of a healthy one. Some condemn the mother and / or father who refused to raise a sick child. But, as the Gospel tells us: "Judge not, and you will not be judged." A child is abandoned for a variety of reasons, both on the part of the mother and / or father (social, material, age, etc.) and the child (severity of the disease, possibilities and prospects for treatment, etc.). The so-called abandoned children can be both sick and practically healthy people, regardless of age: both newborns and infants, and older ones.

For various reasons, the spouses decide to take a child into the family from an orphanage or immediately from a maternity hospital. Less often, this, from our point of view, humane civil act is performed by single women. It happens that disabled children leave the orphanage and their named parents deliberately take into the family a child with Down's disease or with cerebral palsy and other diseases.

The objective of this work is to highlight the clinical and genetic features of the most common hereditary diseases that manifest themselves in a child immediately after birth and at the same time, based on the clinical picture of the disease, a diagnosis can be made, or during subsequent years of the child's life, when the pathology is diagnosed depending on time. the appearance of the first symptoms specific to this disease. Some diseases can be detected in a child even before the onset of clinical symptoms with the help of a number of laboratory biochemical, cytogenetic and molecular genetic studies.

The probability of having a child with a congenital or hereditary pathology, the so-called population or general statistical risk, equal to 3-5%, haunts every pregnant woman. In some cases, it is possible to predict the birth of a child with a particular disease and diagnose pathology already in the period of intrauterine development of the child. Some congenital malformations and diseases are established in the fetus using laboratory biochemical, cytogenetic and molecular genetic methods, more precisely, a set of prenatal (prenatal) diagnostic methods.

We are convinced that all children offered for adoption/adoption should be examined in the most detailed manner by all medical specialists in order to exclude the relevant profile pathology, including examination and examination by a geneticist. In this case, all known data about the child and his parents must be taken into account.

There are 46 chromosomes in the nucleus of every cell in the human body, i.e. 23 pairs that contain all hereditary information. A person receives 23 chromosomes from a mother with an egg and 23 from a father with a sperm. When these two sex cells merge, the result that we see in the mirror and around us is obtained. The study of chromosomes is carried out by a cytogenetic specialist. For this purpose, blood cells called lymphocytes are used, which are specially processed. A set of chromosomes, distributed by a specialist in pairs and by serial number - the first pair, etc., is called a karyotype. We repeat, in the nucleus of each cell there are 46 chromosomes or 23 pairs. The last pair of chromosomes is responsible for the sex of a person. In girls, these are the XX chromosomes, one of them is received from the mother, the other from the father. Boys have XY sex chromosomes. The first is from the mother and the second from the father. Half of the spermatozoa contain an X chromosome and the other half a Y chromosome.

There is a group of diseases caused by a change in the set of chromosomes. The most frequent of these is Down's disease(one in 700 newborns). The diagnosis of this disease in a child should be made by a neonatologist in the first 5-7 days of the newborn's stay in the maternity hospital and confirmed by examining the child's karyotype. In Down syndrome, the karyotype is 47 chromosomes, the third chromosome is found at the 21st pair. Girls and boys suffer from this chromosomal pathology in the same way.

Only girls can Shereshevsky-Turner disease. The first signs of pathology are most often noticeable at the age of 10-12, when the girl has a small stature, low-set hair at the back of her head, at 13-14 years there are no hints of menstruation. There is a slight lag in mental development. The leading symptom in adult patients with Shereshevsky-Turner disease is infertility. The karyotype of such a patient is 45 chromosomes. One X chromosome is missing. The frequency of the disease is 1 per 3,000 girls and among girls 130-145 cm tall - 73 per 1000.

Only seen in males Klinefelter's disease, the diagnosis of which is most often established at the age of 16-18. The patient has a high growth (190 cm and above), often a slight lag in mental development, long arms disproportionately tall, covering the chest when it is girthed. In the study of the karyotype, 47 chromosomes are observed - 47, XXY. In adult patients with Kleinfelter's disease, the leading symptom is infertility. The prevalence of the disease is 1:18,000 healthy men, 1:95 mentally retarded boys, and one in 9 infertile men.

We have described the most common chromosomal diseases above. More than 5,000 diseases of a hereditary nature are classified as monogenic, in which there is a change, a mutation, in any of the 30,000 genes found in the nucleus of a human cell. The work of certain genes contributes to the synthesis (formation) of the protein or proteins corresponding to this gene, which are responsible for the functioning of cells, organs and body systems. Violation (mutation) of a gene leads to a violation of protein synthesis and further disruption of the physiological function of cells, organs and body systems in which this protein is involved. Let's take a look at the most common of these diseases.

All children under the age of 2-3 months should certainly undergo a special biochemical study of urine to exclude them from phenylketonuria or pyruvic oligophrenia. With this hereditary disease, the patient's parents are healthy people, but each of them is a carrier of exactly the same pathological gene (the so-called recessive gene) and with a risk of 25% they may have a sick child. Most often, such cases occur in related marriages. Phenylketonuria is one of the most common hereditary diseases. The frequency of this pathology is 1:10,000 newborns. The essence of phenylketonuria is that the amino acid phenylalanine is not absorbed by the body and its toxic concentrations adversely affect the functional activity of the brain and a number of organs and systems. Lagging mental and motor development, epileptiform-like seizures, dyspeptic manifestations (disorders of the gastrointestinal tract) and dermatitis (skin lesions) are the main clinical manifestations of this disease. Treatment consists mainly in a special diet and the use of amino acid mixtures devoid of the amino acid phenylalanine.

Children under 1-1.5 years old are recommended to be diagnosed for the detection of a severe hereditary disease - cystic fibrosis. With this pathology, damage to the respiratory system and the gastrointestinal tract is observed. The patient has symptoms of chronic inflammation of the lungs and bronchi in combination with dyspeptic manifestations (diarrhea, followed by constipation, nausea, etc.). The frequency of this disease is 1:2500. Treatment consists in the use of enzyme preparations that support the functional activity of the pancreas, stomach and intestines, as well as the appointment of anti-inflammatory drugs.

More often, only after a year of life, clinical manifestations of a common and well-known disease are observed - hemophilia. Boys mostly suffer from this pathology. The mothers of these sick children are carriers of the mutation. Alas, sometimes nothing is written about the mother and her relatives in the child's medical record. Violation of blood clotting, observed in hemophilia, often leads to severe joint damage (hemorrhagic arthritis) and other lesions of the body, with any cuts, prolonged bleeding is observed, which can be fatal for a person.

At 4-5 years of age and only boys show clinical signs Duchenne myodystrophy. As with hemophilia, the mother is a carrier of the mutation, i. "conductor" or transmitter. Skeleton-striped muscles, more simply, the muscles of the first legs, and over the years and all other parts of the body, are replaced by connective tissue that is incapable of contraction. The patient is waiting for complete immobility and death, more often in the second decade of life. To date, an effective therapy for Duchenne myodystrophy has not been developed, although many laboratories in the world, including ours, are conducting research on the use of genetic engineering methods in this pathology. Impressive results have already been obtained in the experiment, allowing one to look with optimism into the future of such patients.

We have indicated the most common hereditary diseases that are detected using molecular diagnostic techniques even before the onset of clinical symptoms. We believe that the study of the karyotype, as well as the examination of the child to exclude common mutations, should be carried out by the institutions where the child is located. In the medical data on the child, along with his blood group and Rh affiliation, karyotype and molecular genetic studies should be indicated that characterize the child's current health status and the likelihood of the most common hereditary diseases in the future.

The proposed surveys will certainly contribute to solving many global problems, both for the child and for people who want to take this child into their family.

V.G. Vakharlovsky - medical geneticist, pediatric neuropathologist of the highest category, candidate of medical sciences. Doctor of the genetic laboratory for prenatal diagnosis of hereditary and congenital diseases BEFORE. Ott — for more than 30 years he has been engaged in medical genetic counseling on the prognosis of the health of children, the study, diagnosis and treatment of children suffering from hereditary and congenital diseases of the nervous system. Author of over 150 publications.

Laboratory for Prenatal Diagnosis of Hereditary and Congenital Diseases (Head Corresponding Member of the Russian Academy of Medical Sciences Professor V.S. Baranov) of the Institute of Obstetrics and Gynecology named after. BEFORE. Otta RAMS, St. Petersburg

As you know, all the features of the appearance and other features of the baby depend on the set of genes that he received from both parents. For most of us, the issue of heredity is only interesting for determining the color of the eyes and hair of the future crumbs, but the importance of genetics does not end there. Recently, even at the stage of planning a child, future parents are strongly advised to seek help from a geneticist, who will determine the likelihood of having a healthy baby in this particular couple. Such a specialist will help calculate the possible risk of developing various genetic diseases that are inherited.

What is genetic inheritance?

The nucleus of every cell in our body has twenty-three pairs of chromosomes, which contain all hereditary information. We receive half of them from the mother's body along with the egg, and half from the father's - along with the sperm. The fusion of these sex cells leads to the birth of a new life. In the event that a parental gene is pathogenic, it can be passed on to the baby. If the carrier of such a code is only the father or only the mother, then the probability of transmission is significantly reduced.

In general, the chance of a child developing a genetic disease is only three to five percent. However, parents should not rely on chance, but take the planning of the baby seriously.
Let's try to figure out what are the hereditary genetic diseases of a person that are inherited.

Down's disease

Down's disease is considered to be the most common genetic disease, as statistics show that one in seven hundred newborns suffers from it. Such a diagnosis is usually made by a neonatologist in the maternity hospital in the first five to seven days of life. To confirm this status of the baby, a study of the karyotype (set of chromosomes) in the baby is carried out. With Down syndrome, a child has one more chromosome - forty-seven pieces. This disease is equally common in boys and girls.

Shershevsky-Turner disease

This disease develops only in girls. Its first signs become noticeable only at the age of ten or twelve and are expressed in small stature and low-set hair at the back of the head. Doctors are usually consulted for lack of menstruation. Over time, the disease leads to some problems in mental development. With Shershevsky-Turner disease, the girl lacks one X chromosome in the karyotype.

Klinefelter's disease

This disease is diagnosed exclusively in males. Most often it is found in the age range from sixteen to eighteen years. Patients are tall - more than one hundred and ninety centimeters, often have some mental retardation and especially long arms, disproportionate to the body, which cover the chest. The study of the karyotype shows one X chromosome more, in some cases it can also be detected by the presence of other extra chromosomes - Y, XX, XY, etc. The main symptom of Klinefelter's disease is infertility.

Phenylcutonuria

This disease is considered to be one of the most common genetic diseases. With such a pathology, the body is not able to absorb the amino acid phenylalanine, which leads to its accumulation in the body. Toxic concentrations of this substance adversely affect the activity of the brain, various organs and systems. The patient has a significant lag in mental and physical development, seizures, problems of the dyspeptic type, as well as dermatitis appear. To correct phenylketonuria, a special diet is used, babies are given special amino acid mixtures that do not contain phenylalanine.

cystic fibrosis

This disease is also considered relatively common. It is manifested by the defeat of all organs that produce mucus - the bronchopulmonary system, digestive tract, liver, sweat, salivary and sex glands suffer. Patients have manifestations of chronic inflammation of the lungs, as well as bronchi, which are combined with dyspeptic problems - diarrhea, which are replaced by constipation, nausea, etc. Therapy involves taking enzyme preparations, as well as anti-inflammatory drugs.

Hemophilia

This disease is diagnosed exclusively in boys, although women are carriers of the affected gene. Hemophilia is characterized by problems with blood clotting, which is fraught with a variety of complications and disorders. With this diagnosis, even a small cut is accompanied by prolonged bleeding, and a bruise leads to the formation of a huge subcutaneous hematoma. Injuries of this kind can be fatal. Hemophilia is treated by administering the missing coagulation factor to the patient. Therapy should continue throughout life.

We have considered only a few of the most well-known and common genetic diseases that are inherited. In fact, their list is much longer. Therefore, all couples who plan to have children should consult with a qualified geneticist who can anticipate possible risks for their common child even before pregnancy.

From parents, a child can acquire not only a certain eye color, height or face shape, but also inherited. What are they? How can you discover them? What classification exists?

Mechanisms of heredity

Before talking about diseases, it is worth understanding what all the information about us is contained in the DNA molecule, which consists of an unimaginably long chain of amino acids. The alternation of these amino acids is unique.

Fragments of the DNA chain are called genes. Each gene contains integral information about one or more characteristics of the body, which is transmitted from parents to children, for example, skin color, hair, character traits, etc. When they are damaged or their work is disturbed, genetic diseases are inherited.

DNA is organized into 46 chromosomes or 23 pairs, one of which is sexual. Chromosomes are responsible for the activity of genes, their copying, as well as repair in case of damage. As a result of fertilization, each pair has one chromosome from the father and the other from the mother.

In this case, one of the genes will be dominant, and the other recessive or suppressed. Simply put, if the gene responsible for eye color is dominant in the father, then the child will inherit this trait from him, and not from the mother.

Genetic diseases

Hereditary diseases occur when abnormalities or mutations occur in the mechanism for storing and transmitting genetic information. An organism whose gene is damaged will pass it on to its offspring in the same way as healthy material.

In the case when the pathological gene is recessive, it may not appear in the next generations, but they will be its carriers. The chance that it will not manifest itself exists when a healthy gene also turns out to be dominant.

Currently, more than 6 thousand hereditary diseases are known. Many of them appear after 35 years, and some may never declare themselves to the owner. Diabetes mellitus, obesity, psoriasis, Alzheimer's disease, schizophrenia and other disorders are manifested with extremely high frequency.

Classification

Genetic diseases that are inherited have a huge number of varieties. To divide them into separate groups, the location of the disorder, causes, clinical picture, and the nature of heredity can be taken into account.

Diseases can be classified according to the type of inheritance and the location of the defective gene. So, it is important whether the gene is located on the sex or non-sex chromosome (autosome), and whether it is suppressive or not. Allocate diseases:

• Autosomal dominant - brachydactyly, arachnodactyly, ectopia of the lens.
• Autosomal recessive - albinism, muscular dystonia, dystrophy.
• Sex-limited (observed only in women or men) - hemophilia A and B, color blindness, paralysis, phosphate-diabetes.

The quantitative and qualitative classification of hereditary diseases distinguishes gene, chromosomal and mitochondrial types. The latter refers to DNA disturbances in mitochondria outside the nucleus. The first two occur in DNA, which is located in the cell nucleus, and have several subtypes:

Causes

Our genes tend not only to accumulate information, but also to change it, acquiring new qualities. This is the mutation. It occurs quite rarely, about 1 time in a million cases, and is transmitted to descendants if it occurs in germ cells. For individual genes, the mutation rate is 1:108.

Mutations are a natural process and form the basis of the evolutionary variability of all living beings. They can be helpful and harmful. Some help us to better adapt to the environment and way of life (for example, the opposed thumb), others lead to diseases.

The occurrence of pathologies in genes is increased by physical, chemical and biological properties. Some alkaloids, nitrates, nitrites, some food additives, pesticides, solvents and petroleum products have this property.

Among the physical factors are ionizing and radioactive radiation, ultraviolet rays, excessively high and low temperatures. The biological causes are rubella viruses, measles, antigens, etc.

genetic predisposition

Parents influence us not only by education. It is known that some people are more likely to develop certain diseases than others due to heredity. A genetic predisposition to diseases occurs when one of the relatives has abnormalities in the genes.

The risk of a particular disease in a child depends on his gender, because some diseases are transmitted only through one line. It also depends on the race of the person and on the degree of relationship with the patient.

If a child is born to a person with a mutation, then the chance of inheriting the disease will be 50%. The gene may well not show itself in any way, being recessive, and in the case of marriage with a healthy person, its chances of being passed on to descendants will be already 25%. However, if the spouse also owns such a recessive gene, the chances of its manifestation in descendants will again increase to 50%.

How to identify the disease?

The genetic center will help to detect the disease or predisposition to it in time. Usually this is in all major cities. Before taking tests, a consultation with a doctor is held to find out what health problems are observed in relatives.

Medico-genetic examination is carried out by taking blood for analysis. The sample is carefully examined in the laboratory for any abnormalities. Expectant parents usually attend such consultations after pregnancy. However, it is worth coming to the genetic center during its planning.

Hereditary diseases seriously affect the mental and physical health of the child, affect life expectancy. Most of them are difficult to treat, and their manifestation is only corrected by medical means. Therefore, it is better to prepare for this even before conceiving a baby.

Down syndrome

One of the most common genetic diseases is Down syndrome. It occurs in 13 cases out of 10,000. This is an anomaly in which a person has not 46, but 47 chromosomes. The syndrome can be diagnosed immediately at birth.

Among the main symptoms are a flattened face, raised corners of the eyes, a short neck, and a lack of muscle tone. The auricles are usually small, the incision of the eyes is oblique, the irregular shape of the skull.

In sick children, concomitant disorders and diseases are observed - pneumonia, SARS, etc. Exacerbations may occur, for example, hearing loss, vision loss, hypothyroidism, heart disease. With Downism, it is slowed down and often remains at the level of seven years.

Constant work, special exercises and preparations significantly improve the situation. There are many cases when people with a similar syndrome could well lead an independent life, find a job and achieve professional success.

Hemophilia

A rare hereditary disease that affects men. Occurs once in 10,000 cases. Hemophilia is not treated and occurs as a result of a change in one gene on the sex X chromosome. Women are only carriers of the disease.

The main characteristic is the absence of a protein that is responsible for blood clotting. In this case, even a minor injury causes bleeding that is not easy to stop. Sometimes it manifests itself only the next day after the bruise.

Queen Victoria of England was a carrier of hemophilia. She passed on the disease to many of her descendants, including Tsarevich Alexei, the son of Tsar Nicholas II. Thanks to her, the disease began to be called "royal" or "Victorian".

Angelman syndrome

The disease is often called "happy doll syndrome" or "Petrushka syndrome", as patients have frequent outbursts of laughter and smiles, chaotic hand movements. With this anomaly, a violation of sleep and mental development is characteristic.

The syndrome occurs once in 10,000 cases due to the absence of certain genes in the long arm of the 15th chromosome. Angelman's disease develops only if the genes are missing from the chromosome inherited from the mother. When the same genes are missing from the paternal chromosome, Prader-Willi syndrome occurs.

The disease cannot be cured completely, but it is possible to alleviate the manifestation of symptoms. For this, physical procedures and massages are carried out. Patients do not become completely independent, but during treatment they can serve themselves.