Hereditary diseases pediatricians, neurologists, endocrinologists
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Hereditary diseases– a large group of human diseases caused by pathological changes in the genetic apparatus. Currently, more than 6 thousand syndromes with a hereditary transmission mechanism are known, and their overall frequency in the population ranges from 0.2 to 4%. Some genetic diseases have a specific ethnic and geographic prevalence, while others occur with equal frequency throughout the world. The study of hereditary diseases is primarily the responsibility of medical genetics, but almost any medical specialist can encounter such a pathology: pediatricians, neurologists, endocrinologists, hematologists, therapists, etc.
Hereditary diseases should be distinguished from congenital and family pathologies. Congenital diseases can be caused not only by genetics, but also by unfavorable exogenous factors affecting the developing fetus (chemical and medicinal compounds, ionizing radiation, intrauterine infections, etc.). At the same time, not all hereditary diseases appear immediately after birth: for example, signs of Huntington's chorea usually first appear at the age of over 40 years. The difference between hereditary and family pathology is that the latter may be associated not with genetic, but with social, everyday or professional determinants.
The occurrence of hereditary diseases is caused by mutations - sudden changes in the genetic properties of an individual, leading to the appearance of new, unusual characteristics. If mutations affect individual chromosomes, changing their structure (due to loss, acquisition, variation in the position of individual sections) or their number, such diseases are classified as chromosomal. The most common chromosomal abnormalities are duodenal and allergic pathology.
Hereditary diseases can appear both immediately after the birth of a child and at different stages of life. Some of them have an unfavorable prognosis and lead to early death, while others do not significantly affect the duration or even quality of life. The most severe forms of hereditary fetal pathology cause spontaneous abortion or are accompanied by stillbirth.
Thanks to the advances in medical development, about a thousand hereditary diseases today can be detected even before the birth of a child using prenatal diagnostic methods. The latter include ultrasound and biochemical screening of the I (10-14 weeks) and II (16-20 weeks) trimesters, which are carried out to all pregnant women without exception. In addition, if there are additional indications, invasive procedures may be recommended: chorionic villus biopsy, amniocentesis, cordocentesis. If the fact of severe hereditary pathology is reliably established, the woman is offered an artificial termination of pregnancy for medical reasons.
All newborns in the first days of their life are also subject to examination for hereditary and congenital metabolic diseases (phenylketonuria, adrenogenital syndrome, congenital adrenal hyperplasia, galactosemia, cystic fibrosis). Other hereditary diseases that were not recognized before or immediately after the birth of a child can be detected using cytogenetic, molecular genetic, and biochemical research methods.
Unfortunately, a complete cure for hereditary diseases is currently not possible. Meanwhile, with some forms of genetic pathology, a significant extension of life and ensuring its acceptable quality can be achieved. In the treatment of hereditary diseases, pathogenetic and symptomatic therapy is used. The pathogenetic approach to treatment involves replacement therapy (for example, with blood coagulation factors in hemophilia), limiting the use of certain substrates for phenylketonuria, galactosemia, maple syrup disease, replenishing the deficiency of a missing enzyme or hormone, etc. Symptomatic therapy includes the use a wide range of medications, physiotherapy, rehabilitation courses (massage, exercise therapy). Many patients with genetic pathology from early childhood need correctional and developmental classes with a speech pathologist and speech therapist.
The possibilities of surgical treatment of hereditary diseases are reduced mainly to the elimination of severe malformations that interfere with the normal functioning of the body (for example, correction of congenital heart defects, cleft lip and palate, hypospadias, etc.). Gene therapy for hereditary diseases is still rather experimental in nature and is still far from widespread use in practical medicine.
The main direction of prevention of hereditary diseases is medical genetic counseling. Experienced geneticists will consult a married couple, predict the risk of having offspring with hereditary pathology, and provide professional assistance in making a decision about childbearing.
V.G. Vakharlovsky - medical geneticist, pediatric neurologist of the highest category, candidate of medical sciences. Doctor of the genetic laboratory for prenatal diagnosis of hereditary and congenital diseases of IAH named after. BEFORE. Otta - for more than 30 years he has been engaged in medical and genetic counseling on the prognosis of the health status of children, the study, diagnosis and treatment of children suffering from hereditary and congenital diseases of the nervous system. Author of more than 150 publications.
Each of us, thinking about a child, dreams of having only a healthy and ultimately happy son or daughter. Sometimes our dreams are crushed, and a child is born seriously ill, but this does not mean at all that this dear, blood (scientifically: biological) child in the overwhelming majority of cases will be less loved and less dear. Of course, when a sick child is born, worries, material costs, and stress - physical and moral - arise immeasurably more than when a healthy child is born. Some people condemn a mother and/or father who abandons a sick child. But, as the Gospel tells us: “Judge not and you will not be judged.” They abandon the child for a variety of reasons, both on the part of the mother and/or father (social, financial, age-related, etc.) and the child (severity of the disease, the possibility and prospects of treatment, etc.). So-called abandoned children can be both sick and practically healthy people, regardless of age: both newborns and infants, as well as older ones.
For various reasons, spouses decide to take a child into the family from an orphanage or directly from a maternity hospital. Less often, this, from our point of view, humane, courageous civil act, is done by single women. It happens that disabled children leave the orphanage and their named parents deliberately take into the family a child with an illness or with cerebral palsy, etc.
The purpose of this work is to highlight the clinical and genetic features of the most common hereditary diseases that appear in a child immediately after birth and then, based on the clinical picture of the disease, a diagnosis can be made, or during the 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 appearance of clinical symptoms using 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 the pathology already in the prenatal period. Some congenital defects and diseases are diagnosed in the fetus using laboratory-biochemical, cytogenetic and molecular genetic techniques, or more precisely, a set of prenatal (antenatal) diagnostic methods.
We are convinced that all children offered for adoption should be examined in detail by all medical specialists in order to exclude relevant specialized pathologies, including examination and examination by a geneticist. In this case, all known data about the child and his parents must be taken into account.
Chromosomal mutations
In the nucleus of each cell of the human body there are 46 chromosomes, i.e. 23 pairs containing all hereditary information. A person receives 23 chromosomes from the mother with the egg and 23 from the father with the 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 cytogeneticist. For this purpose, blood cells called lymphocytes are used, which are specially treated. A set of chromosomes, distributed by a specialist into pairs and by serial number - the first pair, etc., is called a karyotype. We repeat, the nucleus of each cell contains 46 chromosomes or 23 pairs. The last pair of chromosomes determines the sex of a person. In girls, these are XX chromosomes, one of them is received from the mother, the other from the father. Boys have XY sex chromosomes. The first is received from the mother and the second from the father. Half of the sperm contain the X chromosome and the other half the Y chromosome.
There is a group of diseases that are caused by a change in the set of chromosomes. The most common of these is Down syndrome (one in 700 newborns). The diagnosis of this disease in a child must 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 on the 21st pair. Girls and boys suffer from this chromosomal pathology equally.
Only girls can have Shereshevsky-Turner disease. The first signs of pathology are most often noticeable at 10-12 years of age, when the girl is small in stature, low-set hair on the back of her head, and at 13-14 years old there is no hint of menstruation. There is a slight mental retardation. 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 incidence of the disease is 1 in 3,000 girls and among girls with a height of 130-145 cm - 73 in 1,000.
Only males experience Kleinfelter's disease, the diagnosis of which is most often made at 16-18 years of age. The patient has a high height (190 cm and above), often a slight mental retardation, long arms disproportionate to the height, covering the chest when circling it. When studying 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 boys with mental retardation and one in 9 men who are infertile.
Above we have described the most common chromosomal diseases. 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 systems of the body. A disruption (mutation) of a gene leads to disruption of protein synthesis and further disruption of the physiological function of cells, organs and body systems in which the protein is involved. Let's look at the most common of these diseases.
Today, gynecologists advise all women to plan their pregnancy. After all, in this way many hereditary diseases can be avoided. This is possible with a thorough medical examination of both spouses. There are two points regarding the issue of hereditary diseases. The first is a genetic predisposition to certain diseases, which manifests itself as the child grows up. For example, diabetes mellitus, which one of the parents suffers from, can appear in children in adolescence, and hypertension - after 30 years. The second point is the direct genetic diseases with which the child is born. We will talk about them today.
The most common genetic diseases in children: description
The most common hereditary disease in children is Down syndrome. It occurs in 1 case out of 700. The diagnosis of the child is made by a neonatologist while the newborn is in the maternity hospital. In Down syndrome, the child's karyotype contains 47 chromosomes, that is, the extra chromosome is the cause of the disease. You should know that both girls and boys are equally susceptible to this chromosomal pathology. Visually, these are children with a specific facial expression who are lagging behind in mental development.
Girls are more often affected by Shereshevsky-Turner disease. And the symptoms of the disease appear at the age of 10-12: patients are short in stature, the hair on the back of the head is low-set, and at the age of 13-14 they do not experience puberty and do not have periods. Such children have a slight mental retardation. The leading symptom of this hereditary disease in an adult woman is infertility. The karyotype for this disease is 45 chromosomes, that is, one chromosome is missing. The prevalence rate of Shereshevsky-Turner disease is 1 case in 3000. And among girls up to 145 centimeters tall, it is 73 cases in 1000.
Only the male sex is characterized by Kleinfelter's disease. This diagnosis is established at the age of 16-18 years. Signs of the disease are tall height (190 centimeters or even higher), mild mental retardation, disproportionately long arms. The karyotype in this case is 47 chromosomes. A characteristic symptom for an adult man is infertility. Kleinfelter's disease occurs in 1 in 18,000 cases.
Manifestations of a fairly well-known disease - hemophilia - are usually observed in boys after one year of life. Mostly representatives of the stronger half of humanity suffer from pathology. Their mothers are only carriers of the mutation. Bleeding disorders are the main symptom of hemophilia. This often leads to the development of severe joint damage, for example, hemorrhagic arthritis. In hemophilia, any injury that cuts the skin causes bleeding, which can be fatal for a man.
Another severe hereditary disease is cystic fibrosis. Typically, children under one and a half years of age need to be diagnosed to detect this disease. Its symptoms are chronic inflammation of the lungs with dyspeptic symptoms in the form of diarrhea, followed by constipation and nausea. The incidence of the disease is 1 case in 2500.
Rare hereditary diseases in children
There are also genetic diseases that many of us have never heard of. One of them appears at the age of 5 years and is called Duchenne muscular dystrophy.
The carrier of the mutation is the mother. The main symptom of the disease is the replacement of skeletal-striated muscles with connective tissue incapable of contraction. Such a child will eventually face complete immobility and death in the second decade of life. Today there is no effective therapy for Duchenne muscular dystrophy, despite many years of research and the use of genetic engineering.
Another rare genetic disease is osteogenesis imperfecta. This is a genetic pathology of the musculoskeletal system, which is characterized by bone deformation. Osteogenesis is characterized by a decrease in bone mass and increased fragility. There is an assumption that the cause of this pathology lies in a congenital disorder of collagen metabolism.
Progeria is a fairly rare genetic defect that results in premature aging of the body. There are 52 cases of progeria recorded worldwide. Up to six months, children are no different from their peers. Then their skin begins to become wrinkled. The body exhibits symptoms of aging. Children with progeria usually do not live beyond the age of 15. The disease is caused by gene mutations.
Ichthyosis is a hereditary skin disease that occurs as a dermatosis. Ichthyosis is characterized by a violation of keratinization and manifests itself as scales on the skin. The cause of ichthyosis is also a gene mutation. The disease occurs in one case in several tens of thousands.
Cystinosis is a disease that can turn a person into stone. The human body accumulates too much cystine (an amino acid). This substance turns into crystals, causing hardening of all cells in the body. The man gradually turns into a statue. Typically, such patients do not live to see their 16th birthday. The peculiarity of the disease is that the brain remains intact.
Cataplexy is a disease that has strange symptoms. With the slightest stress, nervousness, or nervous tension, all the muscles of the body suddenly relax - and the person loses consciousness. All his experiences end in fainting.
Another strange and rare disease is extrapyramidal system syndrome. The second name of the disease is the dance of St. Vitus. Its attacks overtake a person suddenly: his limbs and facial muscles twitch. As it develops, extrapyramidal system syndrome causes changes in the psyche and weakens the mind. This disease is incurable.
Acromegaly has another name - gigantism. The disease is characterized by high human stature. The disease is caused by excessive production of the growth hormone somatotropin. The patient always suffers from headaches and drowsiness. Acromegaly today also has no effective treatment.
All these genetic diseases are difficult to treat, and more often they are completely incurable.
How to identify a genetic disease in a child
The level of modern medicine makes it possible to prevent genetic pathologies. To do this, pregnant women are asked to undergo a series of studies to determine heredity and possible risks. In simple words, genetic tests are done to identify the propensity of the future baby to hereditary diseases. Unfortunately, statistics record an increasing number of genetic abnormalities in newborn children. And practice shows that most genetic diseases can be avoided by treating them before pregnancy or by terminating a pathological pregnancy.
Doctors emphasize that the ideal option for future parents is to test for genetic diseases at the stage of pregnancy planning.
In this way, the risk of transmitting hereditary disorders to the future baby is assessed. To do this, a couple planning a pregnancy is advised to consult a geneticist. Only the DNA of future parents allows us to assess the risks of giving birth to children with genetic diseases. In this way, the overall health of the unborn child is predicted.
The undoubted advantage of genetic analysis is that it can even prevent miscarriage. But, unfortunately, according to statistics, women most often resort to genetic testing after a miscarriage.
What influences the birth of unhealthy children
So, genetic tests make it possible to assess the risks of having unhealthy children. That is, a geneticist can state that the risk of having a baby with Down syndrome, for example, is 50 to 50. What factors influence the health of the unborn child? Here they are:
- Age of parents. With age, genetic cells accumulate more and more “damages”. This means that the older the father and mother, the higher the risk of having a baby with Down syndrome.
- Close relationship of parents. Both first and second cousins are more likely to carry the same diseased genes.
- The birth of sick children to parents or direct relatives increases the chances of having another baby with genetic diseases.
- Chronic diseases of a familial nature. If both father and mother suffer, for example, from multiple sclerosis, then the likelihood of the disease affecting the unborn baby is very high.
- Parents' belonging to certain ethnic groups. For example, Gaucher's disease, manifested by bone marrow damage and dementia, is more common among Ashkenazi Jews, Wilson's disease - among the peoples of the Mediterranean.
- Unfavorable external environment. If future parents live near a chemical plant, nuclear power plant, or cosmodrome, then polluted water and air contribute to gene mutations in children.
- Exposure to radiation on one of the parents also increases the risk of gene mutations.
So, today, future parents have every chance and opportunity to avoid the birth of sick children. A responsible attitude towards pregnancy and its planning will allow you to fully experience the joy of motherhood and fatherhood.
Especially for - Diana Rudenko
Every gene in the human body carries unique information contained in DNA. The genotype of a particular individual provides both its unique external characteristics and largely determines the state of its health.
Medical interest in genetics has been growing steadily since the second half of the 20th century. The development of this field of science opens up new methods for studying diseases, including rare ones that were considered incurable. To date, several thousand diseases have been discovered that completely depend on a person’s genotype. Let us consider the causes of these diseases, their specificity, what methods of diagnosis and treatment are used by modern medicine.
Types of genetic diseases
Genetic diseases are considered to be inherited diseases that are caused by mutations in genes. It is important to understand that congenital defects that appear as a result of intrauterine infections, the pregnant woman taking illegal drugs and other external factors that could affect pregnancy are not related to genetic diseases.
Human genetic diseases are divided into the following types:
Chromosomal aberrations (rearrangements)
This group includes pathologies associated with changes in the structural composition of chromosomes. These changes are caused by chromosome breakage, which leads to redistribution, doubling or loss of genetic material in them. It is this material that must ensure the storage, reproduction and transmission of hereditary information.
Chromosomal rearrangements lead to a genetic imbalance, which negatively affects the normal course of development of the body. Aberrations manifest themselves in chromosomal diseases: cry-the-cat syndrome, Down syndrome, Edwards syndrome, polysomies on the X chromosome or Y chromosome, etc.
The most common chromosomal abnormality in the world is Down syndrome. This pathology is caused by the presence of one extra chromosome in the human genotype, that is, the patient has 47 chromosomes instead of 46. People with Down syndrome have the 21st pair (there are 23 in total) of chromosomes in three copies, rather than the required two. There are rare cases when this genetic disease is the result of a translocation of chromosome 21 or mosaicism. In the vast majority of cases, the syndrome is not a hereditary disorder (91 out of 100).
Monogenic diseases
This group is quite heterogeneous in terms of clinical manifestations of diseases, but each genetic disease here is caused by DNA damage at the gene level. To date, over 4,000 monogenic diseases have been discovered and described. These include diseases with mental retardation, hereditary metabolic diseases, isolated forms of microcephaly, hydrocephalus and a number of other diseases. Some of the diseases are noticeable already in newborns, others make themselves felt only during puberty or when a person reaches 30–50 years of age.
Polygenic diseases
These pathologies can be explained not only by genetic predisposition, but also, to a large extent, by external factors (poor nutrition, poor environment, etc.). Polygenic diseases are also called multifactorial. This is justified by the fact that they appear as a result of the actions of many genes. The most common multifactorial diseases include: rheumatoid arthritis, hypertension, coronary heart disease, diabetes mellitus, liver cirrhosis, psoriasis, schizophrenia, etc.
These diseases make up about 92% of the total number of pathologies transmitted by inheritance. With age, the incidence of diseases increases. In childhood, the number of patients is at least 10%, and in the elderly - 25-30%.
To date, several thousand genetic diseases have been described, here is just a short list of some of them:
| The most common genetic diseases | The rarest genetic diseases |
|---|---|
|
Hemophilia (blood clotting disorder) |
Capgras delusion (a person believes that someone close to him has been replaced by a clone). |
|
Colorblindness (inability to distinguish colors) |
Klein-Levin syndrome (excessive sleepiness, behavioral disturbances) |
|
Cystic fibrosis (respiratory dysfunction) |
Elephantiasis (painful skin growths) |
|
Spina bifida (vertebrae do not close around the spinal cord) |
Cicero (psychological disorder, desire to eat inedible things) |
|
Tay-Sachs disease (CNS damage) |
Stendhal syndrome (rapid heartbeat, hallucinations, loss of consciousness when seeing works of art) |
|
Klinefelter syndrome (androgen deficiency in men) |
Robin's syndrome (maxillofacial defect) |
|
Prader-Willi syndrome (delayed physical and intellectual development, defects in appearance) |
Hypertrichosis (excessive hair growth) |
|
Phenylketonuria (disorder of amino acid metabolism) |
Blue skin syndrome (blue skin color) |
Some genetic diseases can appear literally in every generation. As a rule, they do not appear in children, but with age. Risk factors (poor environment, stress, hormonal imbalances, poor nutrition) contribute to the manifestation of a genetic error. Such diseases include diabetes, psoriasis, obesity, hypertension, epilepsy, schizophrenia, Alzheimer's disease, etc.
Diagnosis of gene pathologies
Not every genetic disease is detected from the first day of a person’s life; some of them manifest themselves only after several years. In this regard, it is very important to undergo timely research for the presence of gene pathologies. Such diagnostics can be carried out both at the stage of pregnancy planning and during the period of bearing a child.
There are several diagnostic methods:
Biochemical analysis
Allows you to identify diseases associated with hereditary metabolic disorders. The method involves a human blood test, qualitative and quantitative study of other biological fluids of the body;
Cytogenetic method
Identifies the causes of genetic diseases that lie in disturbances in the organization of cellular chromosomes;
Molecular cytogenetic method
An improved version of the cytogenetic method, which makes it possible to detect even microchanges and the smallest chromosome breaks;
Syndromological method
A genetic disease in many cases may have the same symptoms that will coincide with the manifestations of other, non-pathological diseases. The method consists in the fact that with the help of a genetic examination and special computer programs, from the entire spectrum of symptoms, only those that specifically indicate a genetic disease are isolated.
Molecular genetic method
At the moment it is the most reliable and accurate. It makes it possible to study human DNA and RNA and detect even minor changes, including in the nucleotide sequence. Used to diagnose monogenic diseases and mutations.
Ultrasound examination (ultrasound)
To identify diseases of the female reproductive system, ultrasound of the pelvic organs is used. Ultrasound is also used to diagnose congenital pathologies and some chromosomal diseases of the fetus.
It is known that about 60% of spontaneous miscarriages in the first trimester of pregnancy are due to the fact that the fetus had a genetic disease. The mother's body thus gets rid of the non-viable embryo. Inherited genetic diseases can also cause infertility or repeated miscarriages. Often a woman has to undergo many inconclusive examinations until she consults a geneticist.
The best prevention of the occurrence of a genetic disease in the fetus is a genetic examination of the parents during pregnancy planning. Even being healthy, a man or woman can carry damaged gene sections in their genotype. A universal genetic test can detect more than a hundred diseases that are based on gene mutations. Knowing that at least one of the future parents is a carrier of the disorder, the doctor will help you choose adequate tactics for preparing for pregnancy and its management. The fact is that gene changes that accompany pregnancy can cause irreparable harm to the fetus and even become a threat to the life of the mother.
During a woman's pregnancy, with the help of special studies, genetic diseases of the fetus are sometimes diagnosed, which may raise the question of whether it is worth continuing the pregnancy at all. The earliest time for diagnosing these pathologies is the 9th week. This diagnosis is carried out using the safe, non-invasive DNA test Panorama. The test consists of taking blood from a vein from the expectant mother, using the sequencing method to isolate the genetic material of the fetus from it and studying it for the presence of chromosomal abnormalities. The study can identify abnormalities such as Down syndrome, Edwards syndrome, Patau syndrome, microdeletion syndromes, sex chromosome pathologies and a number of other anomalies.
An adult, after passing genetic tests, can find out about his predisposition to genetic diseases. In this case, he will have a chance to resort to effective preventive measures and prevent the occurrence of a pathological condition by being observed by a specialist.
Treatment of genetic diseases
Any genetic disease presents difficulties for medicine, especially since some of them are quite difficult to diagnose. A huge number of diseases cannot be cured in principle: Down syndrome, Klinefelter syndrome, cystic fibrosis, etc. Some of them seriously reduce human life expectancy.
Main treatment methods:
- Symptomatic
Relieves symptoms that cause pain and discomfort, prevents the progression of the disease, but does not eliminate its cause.
geneticist
Kyiv Yulia Kirillovna
If you have:
- questions arose regarding the results of prenatal diagnostics;
- poor screening results
*consultation is carried out for residents of any region of Russia via the Internet. For residents of Moscow and the Moscow region, a personal consultation is possible (bring your passport and a valid compulsory medical insurance policy with you)
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All genetic diseases, of which several thousand are known today, are caused by anomalies in the genetic material (DNA) of a person.
Genetic diseases can be associated with a mutation of one or more genes, with a violation of the arrangement, absence or duplication of entire chromosomes (chromosomal diseases), as well as with maternally transmitted mutations in the genetic material of mitochondria (mitochondrial diseases).
More than 4,000 diseases associated with a defect in one gene (single gene disorders) have been described.
A little about genetic diseases
Medicine has long known that different ethnic groups have a predisposition to certain genetic diseases. For example, people from the Mediterranean region suffer from thalassemia more often than others. We know that the age of the mother greatly influences the risk of a number of genetic diseases in the child.It is also known that some genetic diseases arose in us as an attempt by the body to resist the environment. Sickle cell anemia, according to modern data, originated in Africa, where for many thousands of years malaria was a real scourge of humanity. In sickle cell anemia, people have a mutation in their red blood cells that makes the host resistant to Plasmodium falciparum.
Today, scientists have developed tests for hundreds of genetic diseases. We can test for cystic fibrosis, Down syndrome, fragile X syndrome, hereditary thrombophilias, Bloom's syndrome, Canavan disease, Fanconi anemia, familial dysautonomia, Gaucher disease, Niemann-Pick disease, Klinefelter syndrome, thalassemias and many other diseases.
Cystic fibrosis.
Cystic fibrosis, known in English literature as cystic fibrosis, is one of the most common genetic diseases, especially among people from the Caucasus and Ashkenazi Jews. It is caused by a deficiency of a protein that controls the balance of chlorides in cells. The result of a deficiency of this protein is thickening and disruption of the properties of the secretion of the glands. Cystic fibrosis manifests itself as dysfunction of the respiratory system, digestive tract, and reproductive system. Symptoms can range from mild to very severe. For the disease to occur, both parents must be carriers of the defective genes.Down syndrome.
This is the most well-known chromosomal disorder and occurs due to the presence of excess genetic material on chromosome 21. Down syndrome is registered in 1 child in 800-1000 newborns. This disease can be easily detected through prenatal screening. The syndrome is characterized by abnormalities in facial structure, decreased muscle tone, malformations of the cardiovascular and digestive systems, as well as developmental delays. Children with Down syndrome have symptoms ranging from mild to very severe developmental problems. This disease is equally dangerous for all ethnic groups. The most important risk factor is the age of the mother.Fragile X syndrome.
Fragile X syndrome, or Martin-Bell syndrome, is associated with the most common type of congenital mental retardation. The developmental delay can be very minor or severe, and the syndrome is sometimes associated with autism. This syndrome occurs in 1 in 1,500 men and 1 in 2,500 women. The disease is associated with the presence of abnormal repeating regions on the X chromosome - the more such regions, the more severe the disease.Hereditary bleeding disorders.
Blood coagulation is one of the most complex biochemical processes occurring in the body, therefore there are a huge variety of coagulation disorders at its different stages. Coagulation disorders can cause a tendency to bleed or, conversely, the formation of blood clots.Known diseases include thrombophilia associated with the Leiden mutation (factor V Leiden). There are other genetic clotting disorders, including prothrombin deficiency (factor II), protein C deficiency, protein S deficiency, antithrombin III deficiency, and others.
Everyone has heard about hemophilia - a hereditary coagulation disorder in which dangerous hemorrhages occur in internal organs, muscles, joints, abnormal menstrual bleeding is observed, and any minor injury can lead to irreparable consequences due to the body’s inability to stop bleeding. The most common is hemophilia A (coagulation factor VIII deficiency); Hemophilia B (factor IX deficiency) and hemophilia C (factor XI deficiency) are also known.
There is also a very common von Willebrand disease, in which spontaneous bleeding is observed due to decreased levels of factor VIII. The disease was described in 1926 by Finnish pediatrician von Willebrand. American researchers believe that 1% of the world's population suffers from it, but for most of them the genetic defect does not cause serious symptoms (for example, women may only have heavy menstruation). Clinically significant cases, in their opinion, are observed in 1 person in 10,000, that is, 0.01%.
Familial hypercholesterolemia.
This is a group of inherited metabolic disorders that are characterized by abnormally high levels of lipids and cholesterol in the blood. Familial hypercholesterolemia is associated with obesity, impaired glucose tolerance, diabetes, strokes and heart attacks. Treatment for the disease includes lifestyle changes and a strict diet.Huntington's disease.
Huntington's disease (sometimes Huntington's disease) is an inherited disease that causes gradual degeneration of the central nervous system. Loss of nerve cell function in the brain is accompanied by behavioral changes, unusual jerking movements (chorea), uncontrollable muscle contractions, difficulty walking, memory loss, and difficulty speaking and swallowing.Modern treatment is aimed at combating the symptoms of the disease. Huntington's disease usually begins to manifest itself at the age of 30-40, and until then a person may have no idea about his fate. Less commonly, the disease begins to progress in childhood. It is an autosomal dominant disorder - if one parent has the defective gene, the child has a 50% chance of getting it.
Duchenne muscular dystrophy.
With Duchenne muscular dystrophy, symptoms usually appear before age 6. These include fatigue, muscle weakness (starting in the legs and moving up), possible mental retardation, heart and respiratory problems, and spinal and chest deformities. Progressive muscle weakness leads to disability; by the age of 12, many children are already wheelchair-bound. Boys are sick.Becker muscular dystrophy.
In Becker muscular dystrophy, symptoms resemble Duchenne dystrophy, but occur later and develop more slowly. Muscle weakness in the upper body is not as severe as with the previous type of dystrophy. Boys are sick. The onset of the disease occurs at 10-15 years, and by 25-30 years, patients are usually confined to a wheelchair.Sickle cell anemia.
With this hereditary disease, the shape of red blood cells is disrupted, which become similar to a sickle - hence the name. Changed red blood cells cannot deliver enough oxygen to organs and tissues. The disease leads to severe crises that occur repeatedly or only a few times throughout the patient’s life. In addition to pain in the chest, abdomen and bones, fatigue, shortness of breath, tachycardia, fever, etc. occur.Treatment includes pain medications, folic acid to support hematopoiesis, blood transfusions, dialysis, and hydroxyurea to reduce the frequency of episodes. Sickle cell anemia occurs primarily in people of African and Mediterranean heritage, as well as in South and Central America.
Thalassemia.
Thalassemias (beta thalassemia and alpha thalassemia) are a group of hereditary diseases in which the correct synthesis of hemoglobin is disrupted. As a result, anemia develops. Patients complain of fatigue, shortness of breath, bone pain, they have an enlarged spleen and brittle bones, poor appetite, dark urine, and yellowish skin. Such people are susceptible to infectious diseases.Phenylketonuria.
Phenylketonuria is the result of a deficiency of the liver enzyme that is needed to convert the amino acid phenylalanine into another amino acid, tyrosine. If the disease is not diagnosed early, large amounts of phenylalanine accumulate in the child's body, causing mental retardation, damage to the nervous system and seizures. Treatment consists of a strict diet and the use of tetrahydrobiopterin cofactor (BH4) to reduce phenylalanine levels in the blood.Alpha-1 antitrypsin deficiency.
This disease occurs due to insufficient amounts of the enzyme alpha-1 antitropsin in the lungs and blood, which leads to consequences such as emphysema. Early symptoms of the disease include shortness of breath and wheezing. Other symptoms: weight loss, frequent respiratory infections, fatigue, tachycardia.In addition to those listed above, there are many other genetic diseases. Today there are no radical treatments for them, but gene therapy has enormous potential. Many diseases, especially when diagnosed early, can be successfully controlled, and patients are able to live full, productive lives.