home Endocrinology Hereditary human diseases, their causes and prevention. Hereditary human diseases. List. The most common and dangerous diseases. Treatment of human genetic diseases in Germany

Hereditary human diseases, their causes and prevention. Hereditary human diseases. List. The most common and dangerous diseases. Treatment of human genetic diseases in Germany

Hereditary diseases One of the mysteries remains the emergence of hereditary diseases caused by chromosomal and gene mutations.

As a rule, a child is affected by a hereditary disease when one or both parents are carriers of the defective gene. Less commonly, this occurs as a result of a change in his own gene code under the influence of internal (in the body or cell) or external conditions at the time of conception. If future parents or any of them in their family have had cases of similar illnesses, then before having a baby, they should consult with a geneticist to assess the risk of having sick children.

Types of hereditary diseases

Hereditary diseases usually include:

. Chromosomal diseases arising due to changes in the structure and number of chromosomes (in particular, Down syndrome). They are a common cause of miscarriages, because... a fetus with such severe disorders cannot develop normally. Newborn babies experience varying degrees of damage to the nervous system and the entire body, as well as retardation in physical and mental development.

. Diseases associated with metabolic disorders, which make up a significant part of all hereditary pathologies. This includes diseases that arise from disturbances in amino acid metabolism, fat metabolism (leading, in particular, to impaired brain activity), carbohydrate metabolism, and others. Many of them can only be treated by following a strict diet.

. Immunity disorders lead to a decrease in the production of immunoglobulins - special proteins that provide the body's immune defense. Patients develop sepsis and chronic diseases much more often, and they are more susceptible to attacks from various infections.

. Diseases, affecting the endocrine system, those. disrupting the process of secreting certain hormones, which interferes with normal metabolism, functioning and development of organs.

Newborn screening

There are hundreds of hereditary diseases, and most of them must be combated as early as possible, preferably from birth. Now in many countries, newly born babies are checked for the presence of such diseases - this is called newborn screening. But not all ailments are included in the program.

The criteria for including a disease in screening are defined by WHO:

Relatively common (at least in a given country);

Has serious consequences that can be avoided if treatment is started immediately;

There are no pronounced symptoms in the first days, or even months after birth;

There is an effective treatment;

Mass diagnostics is economically beneficial for the country's healthcare.

Blood for analysis is taken from the heel of all infants in the first week of life. It is applied to a special form with reagents and sent to the laboratory. If a positive reaction is received, the baby will need to undergo the procedure again to confirm or refute the diagnosis.

Newborn screening in Russia

In Russia, since 2006, all newborns are tested for the presence of five diseases.

Cystic fibrosis. Affects the exocrine glands. The mucus and secretions secreted by them become thicker and more viscous, which leads to serious disruptions in the functioning of the respiratory system and gastrointestinal tract, even leading to the death of patients. Expensive treatment is required throughout life, and the earlier it is started, the milder the disease progresses.

Congenital hypothyroidism. Leads to disruption of the production of thyroid hormones, which causes serious delays in physical development and development of the nervous system in children. The disease can be completely stopped if you start taking hormonal medications immediately after it is detected.

Phenylketonuria. It manifests itself in insufficient activity of the enzyme that breaks down the amino acid phenylalanine, which is found in protein foods. Amino acid breakdown products remain in the blood, accumulate there and cause brain damage, mental retardation, and seizures. Patients must follow a strict diet throughout their lives, almost completely eliminating protein foods.

Andrenogenital syndrome. It is a whole group of diseases associated with impaired production of hormones by the adrenal glands. The functioning of the kidneys and cardiovascular system is disrupted, and the development of the genital organs is inhibited. The situation can be corrected only by timely and constant intake of the missing hormones.

Galactosemia. It occurs due to a lack of the enzyme that converts galactose contained in milk sugar into glucose. Excess galactose harms the liver, visual organs, mental and physical development in general. All dairy products must be completely excluded from the patient's diet.

There is no need to be afraid of screening carried out in the maternity hospital - it is completely safe. But if your baby happens to be one of the few thousand who is unlucky enough to be born with one of these diseases, Early treatment will help avoid further complications or even completely eliminate the consequences.

Genetic diseases are diseases that arise in humans due to chromosomal mutations and defects in genes, that is, in the hereditary cellular apparatus. Damage to the genetic apparatus leads to serious and varied problems - hearing loss, visual impairment, delayed psycho-physical development, infertility and many other diseases.

The concept of chromosomes

Each cell of the body has a cell nucleus, the main part of which is made up of chromosomes. A set of 46 chromosomes is a karyotype. 22 pairs of chromosomes are autosomes, and the last 23 pair are sex chromosomes. These are the sex chromosomes that differentiate a man and a woman from each other.

Everyone knows that women have XX chromosomes, and men have XY chromosomes. When a new life arises, the mother passes on the X chromosome, and the father - either X or Y. It is with these chromosomes, or rather with their pathology, that genetic diseases are associated.

The gene can mutate. If it is recessive, then the mutation can be passed on from generation to generation without manifesting itself in any way. If the mutation is dominant, then it will definitely manifest itself, so it is advisable to protect your family by learning about the potential problem in time.

Genetic diseases are a problem in the modern world.

More and more hereditary pathologies are being discovered every year. More than 6,000 names of genetic diseases are already known; they are associated with both quantitative and qualitative changes in the genetic material. According to the World Health Organization, approximately 6% of children suffer from hereditary diseases.

The most unpleasant thing is that genetic diseases can appear only after several years. Parents rejoice at a healthy baby, not suspecting that their children are sick. For example, some hereditary diseases can manifest themselves at the age when the patient himself has children. And half of these children may be doomed if the parent carries a dominant pathological gene.

But sometimes it is enough to know that the child’s body is not able to absorb a certain element. If parents are warned about this in time, then in the future, simply avoiding products containing this component, you can protect the body from manifestations of a genetic disease.

Therefore, it is very important that when planning a pregnancy, a test for genetic diseases is done. If the test shows the likelihood of transmitting the mutated gene to the unborn child, then in German clinics they can carry out gene correction during artificial insemination. Tests can also be done during pregnancy.

In Germany, you can be offered innovative technologies of the latest diagnostic developments that can dispel all your doubts and suspicions. About 1,000 genetic diseases can be detected before a child is born.

Genetic diseases - what are the types?

We will look at two groups of genetic diseases (actually there are more)

1. Diseases with a genetic predisposition.

Such diseases can manifest themselves under the influence of external environmental factors and are very dependent on individual genetic predisposition. Some diseases may appear in older people, while others may appear unexpectedly and early. So, for example, a strong blow to the head can provoke epilepsy, taking an indigestible product can cause severe allergies, etc.

2. Diseases that develop in the presence of a dominant pathological gene.

Such genetic diseases are passed on from generation to generation. For example, muscular dystrophy, hemophilia, six-fingered, phenylketonuria.

Families at high risk of having a child with a genetic disease.

Which families first need to attend genetic consultations and identify the risk of hereditary diseases in their offspring?

1. Consanguineous marriages.

2. Infertility of unknown etiology.

3. Age of parents. It is considered a risk factor if the expectant mother is over 35 years old and the father is over 40 (according to some sources, over 45). With age, more and more damage appears in the reproductive cells, which increases the risk of having a baby with a hereditary pathology.

4. Hereditary family diseases, that is, similar diseases in two or more family members. There are diseases with pronounced symptoms and the parents have no doubt that this is a hereditary disease. But there are signs (microanomalies) that parents do not pay due attention to. For example, an unusual shape of the eyelids and ears, ptosis, coffee-colored spots on the skin, a strange smell of urine, sweat, etc.

5. Complicated obstetric history - stillbirth, more than one spontaneous miscarriage, missed pregnancies.

6. Parents are representatives of a small nationality or come from one small locality (in this case, there is a high probability of consanguineous marriages)

7. The impact of unfavorable household or professional factors on one of the parents (calcium deficiency, insufficient protein nutrition, work in a printing house, etc.)

8. Poor environmental conditions.

9. Use of drugs with teratogenic properties during pregnancy.

10. Diseases, especially viral etiology (rubella, chicken pox), suffered by a pregnant woman.

11. Unhealthy lifestyle. Constant stress, alcohol, smoking, drugs, poor nutrition can cause damage to genes, since the structure of chromosomes under the influence of unfavorable conditions can change throughout life.

Genetic diseases - what are the diagnostic methods?

In Germany, the diagnosis of genetic diseases is highly effective, since all known high-tech methods and absolutely all the capabilities of modern medicine (DNA analysis, DNA sequencing, genetic passport, etc.) are used to determine potential hereditary problems. Let's look at the most common ones.

1. Clinical and genealogical method.

This method is an important condition for high-quality diagnosis of a genetic disease. What does it include? First of all, a detailed interview with the patient. If there is a suspicion of a hereditary disease, then the survey concerns not only the parents themselves, but also all relatives, that is, complete and thorough information is collected about each family member. Subsequently, a pedigree is compiled indicating all the signs and diseases. This method ends with a genetic analysis, on the basis of which a correct diagnosis is made and optimal therapy is selected.

2. Cytogenetic method.

Thanks to this method, diseases that arise due to problems in the cell's chromosomes are determined. The cytogenetic method examines the internal structure and arrangement of chromosomes. This is a very simple technique - a scraping is taken from the mucous membrane of the inner surface of the cheek, then the scraping is examined under a microscope. This method is carried out with parents and family members. A type of cytogenetic method is molecular cytogenetic, which allows you to see the smallest changes in the structure of chromosomes.

3. Biochemical method.

This method, by examining the mother’s biological fluids (blood, saliva, sweat, urine, etc.), can determine hereditary diseases based on metabolic disorders. One of the most famous genetic diseases associated with metabolic disorders is albinism.

4. Molecular genetic method.

This is the most progressive method currently used to identify monogenic diseases. It is very accurate and detects pathology even in the nucleotide sequence. Thanks to this method, it is possible to determine a genetic predisposition to the development of oncology (cancer of the stomach, uterus, thyroid gland, prostate, leukemia, etc.) Therefore, it is especially indicated for persons whose close relatives suffered from endocrine, mental, oncological and vascular diseases.

In Germany, to diagnose genetic diseases, you will be offered the full range of cytogenetic, biochemical, molecular genetic studies, prenatal and postnatal diagnostics, plus neonatal screening of the newborn. Here you can take about 1,000 genetic tests that are approved for clinical use in the country.

Pregnancy and genetic diseases

Prenatal diagnosis provides great opportunities for identifying genetic diseases.

Prenatal diagnosis includes studies such as

chorionic villus biopsy - analysis of fetal chorionic tissue at 7-9 weeks of pregnancy; a biopsy can be performed in two ways - through the cervix or by puncturing the anterior abdominal wall;
amniocentesis - at 16-20 weeks of pregnancy, amniotic fluid is obtained through puncture of the anterior abdominal wall;
Cordocentesis is one of the most important diagnostic methods, as it examines fetal blood obtained from the umbilical cord.

Screening methods such as triple test, fetal echocardiography, and determination of alpha-fetoprotein are also used in diagnosis.

Ultrasound imaging of the fetus in 3D and 4D dimensions can significantly reduce the birth of babies with developmental defects. All these methods have a low risk of side effects and do not adversely affect the course of pregnancy. If a genetic disease is detected during pregnancy, the doctor will suggest certain individual tactics for managing the pregnant woman. In the early stages of pregnancy, German clinics can offer gene correction. If gene correction is carried out in time in the embryonic period, then some genetic defects can be corrected.

Neonatal screening of a child in Germany

Neonatal newborn screening identifies the most common genetic diseases in an infant. Early diagnosis makes it possible to understand that a child is sick even before the first signs of illness appear. Thus, the following hereditary diseases can be identified - hypothyroidism, phenylketonuria, maple syrup disease, adrenogenital syndrome and others.

If these diseases are detected in time, the chance of curing them is quite high. High-quality neonatal screening is also one of the reasons why women fly to Germany to give birth to a child here.

Treatment of human genetic diseases in Germany

Until recently, genetic diseases were not treated; it was considered impossible, and therefore hopeless. Therefore, the diagnosis of a genetic disease was regarded as a death sentence, and at best, one could only count on symptomatic treatment. Now the situation has changed. Progress is noticeable, positive treatment results have appeared, and what’s more, science is constantly discovering new and effective ways to treat hereditary diseases. And although many hereditary diseases cannot be cured today, geneticists are optimistic about the future.

Treatment of genetic diseases is a very complex process. It is based on the same principles of influence as any other disease - etiological, pathogenetic and symptomatic. Let's look briefly at each.

1. Etiological principle of influence.

The etiological principle of influence is the most optimal, since treatment is aimed directly at the causes of the disease. This is achieved using methods of gene correction, isolating the damaged part of DNA, cloning it and introducing it into the body. At the moment, this task is very difficult, but for some diseases it is already feasible

2. Pathogenetic principle of influence.

Treatment is aimed at the mechanism of development of the disease, that is, it changes the physiological and biochemical processes in the body, eliminating defects caused by the pathological gene. As genetics develops, the pathogenetic principle of influence expands, and for different diseases, new ways and possibilities for correcting damaged links will be found every year.

3. Symptomatic principle of influence.

According to this principle, treatment of a genetic disease is aimed at relieving pain and other unpleasant phenomena and preventing further progression of the disease. Symptomatic treatment is always prescribed; it can be combined with other methods of treatment, or it can be an independent and only treatment. This is the prescription of painkillers, sedatives, anticonvulsants and other medications. The pharmacological industry is now very developed, so the range of drugs used to treat (or rather, to alleviate the manifestations of) genetic diseases is very wide.

In addition to drug treatment, symptomatic treatment includes the use of physiotherapeutic procedures - massage, inhalations, electrotherapy, balneotherapy, etc.

Sometimes surgical treatment is used to correct deformities, both external and internal.

Geneticists in Germany already have extensive experience in treating genetic diseases. Depending on the manifestation of the disease and individual parameters, the following approaches are used:

genetic nutrition;
gene therapy,
stem cell transplantation,
organ and tissue transplantation,
enzyme therapy,
hormone and enzyme replacement therapy;
hemosorption, plasmaphoresis, lymphosorption - cleansing the body with special preparations;
surgery.

Of course, treatment of genetic diseases takes a long time and is not always successful. But the number of new approaches to therapy is growing every year, so doctors are optimistic.

Gene therapy

Doctors and scientists around the world place special hopes on gene therapy, thanks to which it is possible to introduce high-quality genetic material into the cells of a sick organism.

Gene correction consists of the following stages:

obtaining genetic material (somatic cells) from the patient;
introduction of a therapeutic gene into this material, which corrects the gene defect;
cloning of corrected cells;
introduction of new healthy cells into the patient’s body.

Gene correction requires great caution, since science does not yet have complete information about the functioning of the genetic apparatus.

List of genetic diseases that can be identified

There are many classifications of genetic diseases, they are arbitrary and differ in the principle of construction. Below we provide a list of the most common genetic and hereditary diseases:

Gunther's disease;
Canavan disease;
Niemann-Pick disease;
Tay-Sachs disease;
Charcot-Marie disease;
hemophilia;
hypertrichosis;
color blindness - insensitivity to color, color blindness is transmitted only with the female chromosome, but the disease affects only men;
Capgras fallacy;
Pelizaeus-Merzbacher leukodystrophy;
Blashko lines;
micropsia;
cystic fibrosis;
neurofibromatosis;
heightened reflection;
porphyria;
progeria;
spina bifida;
Angelman syndrome;
exploding head syndrome;
blue skin syndrome;
Down syndrome;
living corpse syndrome;
Joubert syndrome;
stone man syndrome
Klinefelter's syndrome;
Klein-Levin syndrome;
Martin-Bell syndrome;
Marfan syndrome;
Prader-Willi syndrome;
Robin's syndrome;
Stendhal's syndrome;
Turner syndrome;
elephantiasis;
phenylketonuria.
cicero and others.

In this section we will go into detail about each disease and tell you how some of them can be cured. But it is better to prevent genetic diseases than to treat them, especially since modern medicine does not know how to cure many diseases.

Genetic diseases are a group of diseases that are very heterogeneous in their clinical manifestations. The main external manifestations of genetic diseases:

small head (microcephaly);
microanomalies (“third eyelid”, short neck, unusually shaped ears, etc.)
delayed physical and mental development;
changes in genital organs;
excessive muscle relaxation;
change in the shape of the toes and hands;
violation of psychological status, etc.

Genetic diseases - how to get advice in Germany?

Conversation in genetic consultation and prenatal diagnosis can prevent severe hereditary diseases transmitted at the gene level. The main goal of genetic counseling is to identify the degree of risk of a genetic disease in a newborn.

In order to receive quality consultation and advice on further actions, you need to be serious about communicating with your doctor. Before the consultation, you need to responsibly prepare for the conversation, remember the illnesses that your relatives suffered, describe all health problems and write down the main questions to which you would like to receive answers.

If the family already has a child with an anomaly, with congenital malformations, take his photographs. It is imperative to talk about spontaneous miscarriages, cases of stillbirth, and how the pregnancy went (is going).

A genetic consultation doctor will be able to calculate the risk of having a baby with a severe hereditary pathology (even in the future). When can we talk about a high risk of developing a genetic disease?

a genetic risk of up to 5% is considered low;
no more than 10% - slightly increased risk;
from 10% to 20% - average risk;
above 20% - high risk.

Doctors advise considering a risk of about or above 20% as a reason to terminate the pregnancy or (if one does not exist yet) as a contraindication to conception. But the final decision is made, of course, by the married couple.

The consultation may take place in several stages. When diagnosing a genetic disease in a woman, the doctor develops management tactics before pregnancy and, if necessary, during pregnancy. The doctor talks in detail about the course of the disease, life expectancy for this pathology, all the possibilities of modern therapy, the price component, and the prognosis of the disease. Sometimes gene correction during artificial insemination or during embryonic development allows one to avoid the manifestations of the disease. Every year, new methods of gene therapy and the prevention of hereditary diseases are being developed, so the chances of curing genetic pathology are constantly increasing.

In Germany, methods of combating gene mutations using stem cells are being actively introduced and are already being successfully applied, and new technologies are being considered for the treatment and diagnosis of genetic diseases.

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

Mechanisms of heredity

Before talking about diseases, it is worth understanding what they are. All 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.

The fragments of a chain of DNA 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 trait, etc. When they are damaged or their work is disrupted, genetic diseases that are inherited occur.

DNA is organized into 46 chromosomes or 23 pairs, one of which is the sex chromosome. Chromosomes are responsible for gene activity, copying, and recovery from damage. As a result of fertilization, each couple has one chromosome from the father and another from the mother.

In this case, one of the genes will be dominant, and the other will be recessive or suppressed. To put it simply, if the father’s gene responsible for eye color turns out to be dominant, then the child will inherit this trait from him, and not from the mother.

Genetic diseases

Inherited diseases occur when disturbances or mutations occur in the mechanism for storing and transmitting genetic information. An organism whose gene is damaged will pass it on to its descendants 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 make themselves known to the owner. Diabetes mellitus, obesity, psoriasis, Alzheimer's disease, schizophrenia and other disorders occur with extremely high frequency.

Classification

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

Diseases can be classified according to the type of inheritance and 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. Diseases are distinguished:

Autosomal dominant - brachydactyly, arachnodactyly, ectopia lentis.
Autosomal recessive - albinism, muscular dystonia, dystrophy.
Limited by gender (observed only in women or men) - hemophilia A and B, color blindness, paralysis, phosphate diabetes.

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



Monogenic	Mutations or absence of a gene in nuclear DNA.	Marfan syndrome, adrenogenital syndrome in newborns, neurofibromatosis, hemophilia A, Duchenne myopathy.
Polygenic	Predisposition and action	Psoriasis, schizophrenia, coronary disease, cirrhosis, bronchial asthma, diabetes mellitus.
Chromosomal
	Changes in chromosome structure.	Miller-Dicker, Williams, Langer-Gidion syndromes.
	Change in the number of chromosomes.	Down's, Patau's, Edwards', Klifenter's syndromes.

Causes

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

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

The occurrence of pathologies in genes is increased by physical, chemical and biological factors. 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. Rubella viruses, measles, antigens, etc. act as biological causes.

Genetic predisposition

Parents influence us not only through upbringing. It is known that some people are more likely to develop certain diseases than others due to heredity. 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 person's race and the degree of relationship with the patient.

If a person with the mutation gives birth to a child, the chance of inheriting the disease will be 50%. The gene may well not manifest 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 has such a recessive gene, the chances of its manifestation in the 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 there is one in all major cities. Before taking the tests, a consultation is held with a doctor to find out what health problems are observed in relatives.

A medical 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 and affect life expectancy. Most of them are difficult to treat, and their manifestation can only be 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.

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

Sick children experience concomitant disorders and diseases - pneumonia, ARVI, etc. Exacerbations may occur, for example, loss of hearing, vision, hypothyroidism, heart disease. With downism it is slowed down and often remains at the level of seven years.

Constant work, special exercises and medications significantly improve the situation. There are many cases where people with a similar syndrome were quite able to lead an independent life, find work and achieve professional success.

Hemophilia

A rare hereditary disease that affects men. Occurs once in 10,000 cases. Hemophilia has no cure 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 injury.

Queen Victoria of England was a carrier of hemophilia. She passed the disease on 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 “Parsley syndrome”, as patients experience frequent outbursts of laughter and smiling, and chaotic hand movements. This anomaly is characterized by disturbances in sleep and mental development.

The syndrome occurs once in 10,000 cases due to the absence of certain genes on the long arm of chromosome 15. Angelman disease develops only if 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 completely cured, but it is possible to alleviate the symptoms. For this purpose, physical procedures and massages are performed. Patients do not become completely independent, but during treatment they can take care of themselves.

At the beginning of the 21st century, there are already more than 6 thousand types of hereditary diseases. Now many institutions around the world are studying people, the list of which is huge.

The male population has more and more genetic defects and less and less chances of conceiving a healthy child. All the reasons for the pattern of development of defects are still unclear, but it can be assumed that in the next 100-200 years science will cope with resolving these issues.

What are genetic diseases? Classification

Genetics as a science began its research path in 1900. Genetic diseases are those that are associated with deviations in the human gene structure. Deviations can occur in one gene or in several.

Hereditary diseases:

Autosomal dominant.
Autosomal recessive.
Glued to the floor.
Chromosomal diseases.

The probability for an autosomal dominant disorder is 50%. With autosomal recessive - 25%. Sex-linked diseases are those caused by a damaged X chromosome.

Hereditary diseases

Let us give several examples of diseases, according to the above classification. So, dominant-recessive diseases include:

Marfan syndrome.
Paroxysmal myoplegia.
Thalassemia.
Otosclerosis.

Recessive:

Phenylketonuria.
Ichthyosis.
Other.

Sex-linked diseases:

Hemophilia.
Muscular dystrophy.
Farby's disease.

Also known are chromosomal hereditary human diseases. The list of chromosomal abnormalities is as follows:

Shareshevsky-Turner syndrome.
Down syndrome.

Polygenic diseases include:

Hip dislocation (congenital).
Heart defects.
Schizophrenia.
Cleft lip and palate.

The most common gene abnormality is syndactyly. That is, the fusion of fingers. Syndactyly is the most harmless disorder and can be treated with surgery. However, this deviation accompanies other more serious syndromes.

What diseases are the most dangerous?

Of these listed diseases, the most dangerous hereditary human diseases can be identified. Their list consists of those types of anomalies where trisomy or polysomy occurs in the chromosome set, that is, when instead of a pair of chromosomes there is the presence of 3, 4, 5 or more. There is also 1 chromosome instead of 2. All these deviations occur due to impaired cell division.

The most dangerous hereditary human diseases:

Edwards syndrome.
Spinal muscular amyotrophy.
Patau syndrome.
Hemophilia.
Other diseases.

As a result of such violations, the child lives for a year or two. In some cases, the abnormalities are not so serious, and the child may live to be 7, 8 or even 14 years old.

Down syndrome

Down syndrome is inherited if one or both parents are carriers of defective chromosomes. More precisely, the syndrome is associated with chromosomes (ie 21 chromosomes 3, not 2). Children with Down syndrome have squints, creases in the neck, abnormally shaped ears, heart problems and mental retardation. But the chromosomal abnormality does not pose a danger to the life of newborns.

Now statistics say that out of 700-800 children, 1 is born with this syndrome. Women who want to have a child after 35 are more likely to give birth to such a baby. The probability is somewhere around 1 in 375. But a woman who decides to have a baby at 45 has a probability of 1 in 30.

Acrocraniodysphalangia

The type of inheritance of the anomaly is autosomal dominant. The cause of the syndrome is a disorder in chromosome 10. In science, this disease is called acrocraniodysphalangia, or more simply, Apert syndrome. Characterized by such body structure features as:

brachycephaly (violations of the ratio of the width and length of the skull);
fusion of the coronary sutures of the skull, resulting in hypertension (increased blood pressure inside the skull);
syndactyly;
prominent forehead;
often mental retardation due to the fact that the skull compresses the brain and does not allow nerve cells to grow.

Nowadays, children with Apert syndrome undergo skull enlargement surgery to restore blood pressure. And mental underdevelopment is treated with stimulants.

If a family has a child diagnosed with the syndrome, the likelihood that a second child will be born with the same disorder is very high.

Happy doll syndrome and Canavan-van-Bogaert-Bertrand disease

Let's take a closer look at these diseases. Engelman syndrome can be recognized from 3 to 7 years of age. Children have seizures, poor digestion, and problems with coordination of movements. Most of them have squints and problems with the facial muscles, which is why they often smile on their faces. The child's movements are very constrained. For doctors, this is understandable when a child is trying to walk. Parents in most cases do not know what is happening, much less what it is connected with. A little later, it is noticeable that they cannot speak, they are only trying to mutter something inarticulately.

The reason why a child exhibits the syndrome is a problem on chromosome 15. The disease is extremely rare - 1 case per 15 thousand births.

Another disease, Canavan disease, is characterized by the fact that the child has weak muscle tone and has problems swallowing food. The disease is caused by damage to the central nervous system. The reason is the defeat of one gene on chromosome 17. As a result, the nerve cells of the brain are destroyed with progressive rapidity.

Signs of the disease can be seen at 3 months of age. Canavan's disease manifests itself as follows:

Macrocephaly.
Convulsions appear at one month of age.
The child is unable to hold his head upright.
After 3 months, tendon reflexes increase.
Many children become blind by the age of 2.

As you can see, human hereditary diseases are very diverse. The list, given as an example only, is far from complete.

I would like to note that if both parents have a disorder in one and the same gene, then the chances of giving birth to a sick child are high, but if the abnormalities are in different genes, then there is no need to be afraid. It is known that in 60% of cases, chromosomal abnormalities in the embryo lead to miscarriage. But still, 40% of such children are born and fight for their lives.

Every healthy person has 6-8 damaged genes, but they do not disrupt cell functions and do not lead to disease, since they are recessive (non-manifest). If a person inherits two similar abnormal genes from his mother and father, he becomes ill. The probability of such a coincidence is extremely low, but it increases sharply if the parents are relatives (that is, they have a similar genotype). For this reason, the incidence of genetic abnormalities is high in closed populations.

Each gene in the human body is responsible for the production of a specific protein. Due to the manifestation of a damaged gene, the synthesis of an abnormal protein begins, which leads to impaired cell function and developmental defects.

A doctor can determine the risk of a possible genetic anomaly by asking you about diseases of relatives “up to the third generation” on both your side and your husband’s side.

There are a great many genetic diseases, some of which are very rare.

List of rare hereditary diseases

Here are the characteristics of some genetic diseases.

Down syndrome (or trisomy 21)- a chromosomal disease characterized by mental retardation and impaired physical development. The disease occurs due to the presence of the third chromosome in the 21st pair (in total, a person has 23 pairs of chromosomes). It is the most common genetic disorder, affecting approximately one in 700 births. The incidence of Down syndrome increases in children born to women over 35 years of age. Patients with this disease have a special appearance and suffer from mental and physical retardation.

Turner syndrome- a disease that affects girls, characterized by the partial or complete absence of one or two X chromosomes. The disease occurs in one in 3,000 girls. Girls with this condition are usually very short and their ovaries do not function.

X trisomy syndrome- a disease in which a girl is born with three X chromosomes. This disease occurs on average in one in 1000 girls. Trisomy X syndrome is characterized by slight mental retardation and, in some cases, infertility.

Klinefelter syndrome- a disease in which a boy has one extra chromosome. The disease occurs in one boy out of 700. Patients with Klinefelter syndrome, as a rule, are tall and do not have any noticeable external developmental abnormalities (after puberty, facial hair growth is difficult and the mammary glands are slightly enlarged). The intelligence of patients is usually normal, but speech impairments are common. Men suffering from Klinefelter syndrome are usually infertile.

Cystic fibrosis- a genetic disease in which the functions of many glands are disrupted. Cystic fibrosis affects only Caucasian people. About one in 20 white people has one damaged gene that, if manifested, can cause cystic fibrosis. The disease occurs if a person receives two such genes (from the father and from the mother). In Russia, cystic fibrosis, according to various sources, occurs in one newborn out of 3500-5400, in the USA - in one out of 2500. With this disease, the gene responsible for the production of a protein that regulates the movement of sodium and chlorine through cell membranes is damaged. Dehydration occurs and the viscosity of the gland secretion increases. As a result, a thick secretion blocks their activity. In patients with cystic fibrosis, protein and fat are poorly absorbed, and as a result, growth and weight gain are greatly reduced. Modern treatment methods (taking enzymes, vitamins and a special diet) allow half of patients with cystic fibrosis to live more than 28 years.

Hemophilia- a genetic disease characterized by increased bleeding due to a deficiency of one of the blood clotting factors. The disease is inherited through the female line, and affects the vast majority of boys (on average, one in 8,500). Hemophilia occurs when the genes responsible for the activity of blood clotting factors are damaged. With hemophilia, frequent hemorrhages in the joints and muscles are observed, which can ultimately lead to their significant deformation (that is, to a person’s disability). People with hemophilia should avoid situations that could lead to bleeding. People with hemophilia should not take medications that reduce blood clotting (for example, aspirin, heparin, and some pain relievers). To prevent or stop bleeding, the patient is given a plasma concentrate containing a large amount of the missing coagulation factor.

Tay Sachs disease- a genetic disease characterized by the accumulation of phytanic acid (a product of fat breakdown) in tissues. The disease occurs mainly among Ashkenazi Jews and French Canadians (one in 3,600 newborns). Children with Tay-Sachs disease are delayed in development from an early age, then paralysis and blindness occur. As a rule, patients live up to 3-4 years. There are no treatments for this disease.