Although the vast majority of children are born normal, approximately 1% have some form of congenital abnormality. A huge number of factors can affect how a baby develops in the womb, but many abnormalities can be corrected before or after birth.

CONGENITAL HEART DISEASES

The heart is a complex organ, a significant part of which is formed in the 3-7th week after conception. Congenital heart diseases are quite common and are found in one in a hundred children. The range of deviations is very wide.

A mother with a congenital heart defect, or who has already given birth to a child with such a disease, is at little risk for her next baby. Many heart diseases are associated with genetic disorders such as Down syndrome; and if heart disease is detected, testing may be suggested to identify such problems.

How are heart diseases diagnosed? Most diseases are detected using ultrasound examination at 18-22 weeks, since many defects cannot be identified earlier. If you have a history of heart disease in your family, regular ultrasound examinations should be performed during pregnancy. However, ultrasound does not “catch” some diseases at all, and in general, approximately 40% of diseases are missed.

Treatment

Currently, methods of surgical intrauterine treatment are being developed, so in the future some abnormalities will be eliminated even before birth. The attitude towards the disease after birth will depend on the severity of the diagnosis. If the problem is minor, the child usually remains with the mother under the supervision of a hospital pediatrician. More serious illnesses, leading to a lack of oxygen in the body, require specialist supervision. This means that childbirth should occur when the doctor advises. Many heart diseases are subject to surgical treatment, although there are some that will not allow the baby to survive outside the womb.

Polyhydramnios(hydramnios) This is a heart condition in a child; on ultrasound examination, the skin appears swollen, fluid is found in the chest and abdominal cavity. There may be various reasons, including blood type incompatibility, which is determined during pregnancy.

How is polyhydramnios diagnosed?

Treatment

Treatment depends on the severity of the condition. In some cases, such as anemia, treatment is possible, but in others associated with serious heart disease, it is not. Children with incompatible blood types can be treated with intrauterine blood transfusion. Whether a child with polyhydramnios will survive depends on the diagnosis and

how sick he is at the time of diagnosis. Very sick children do not survive.

Vascular septum of the heart

Commonly known as a "hole in the heart". Occurs when tissue divides between the smaller and larger cavities of the heart. A small cleft may not be detected immediately, but later life. Non-unions detected during pregnancy are usually large in size or associated with other diseases.

How is nonunion diagnosed?

heart septum

Using ultrasound examination.

Treatment

Minor defects do not always require surgical intervention, but in other cases it is a necessity.

Diseases associated with the flow of blood from the heart

They occur because blood vessels do not communicate properly or because valves do not form properly. Diseases of this kind are usually complex and may be associated with non-closure of the septum of the heart.

How are diseases associated with the flow of blood from the heart diagnosed? Using ultrasound examination.

Treatment

If the heart valves are damaged, surgery is more difficult and less likely to succeed in the long term. Many such conditions present exceptional difficulties. If there are such abnormalities in the child, parents should consult with a specialist during pregnancy to choose best option treatment.

Neural tube defects

One of the most common diseases, a neural tube defect is a failure of the brain and spinal cord to develop

appropriately during the first four weeks of pregnancy. The condition affects one in 2,500 children living in the UK and leads to varying degrees birth defects. In general, it is registered in significantly more pregnancies, but parents prefer to terminate it if the disease is determined to be early stage.

Spina bifida without spina bifida is the most mild form a disease in which there is no damage to the spinal cord or its membranes and one or two vertebrae are formed incorrectly. In this form, the spinal cord is covered by skin, so problems usually do not occur. Sometimes the disease is detected only during X-ray examination in the process of life. Sometimes a tuft of hair grows around the site of the disease or the skin has dimples.

Myelomeningocele is a more severe form of spina bifida. In this case, the spine has damage, sometimes reaching the size of an orange, where nerve tissues, muscles and cerebrospinal fluid enter. The defect leads to nerve damage, resulting in problems with muscle control, bladder and intestines. Hydrocephalus is associated with this.

Anencephaly (congenital absence of the brain) is the most serious neural tube defect. A hole in the top of the tube results in a partial lack of formation of the skull and brain. After birth, such children do not survive.

How are neural tube defects diagnosed?

Spina bifida can be detected at 16 weeks by examination serous fluid very effective in identifying children with significant neural tube defects.

Treatment

Depends on the type and size of the neural tube defect and its severity, as determined by ultrasound and tomography after delivery. If the child has a clear defect, this will require surgery spinal cord. Although surgery will correct the defect, it will not repair the nerves, which may not develop properly. Hydrocephalus also requires surgery to relieve the baby after birth.

Preventive measures

Although the cause of neural tube defects is unclear, there is now clear evidence that folic acid, a vitamin found in leafy vegetables, must be present in the body at initial stage pregnancy to allow the spine to close properly. Since it is difficult to achieve the recommended doses through nutrition alone, it is recommended to take the drug for three months before conception and until the 12th week of pregnancy. folic acid. Experts suggest that all women of childbearing age should consume 400 micrograms of folic acid daily. Mothers who have had a previous child with spina bifida or anencephaly, or who are taking certain medications, such as to treat epilepsy, should receive higher doses of folic acid - 5 mg. It can be prescribed by a doctor or purchased in pharmacies and supermarkets.

Hydrocephalus

This is a buildup of cerebrospinal fluid in the head caused by a blockage drainage system around the brain. Sometimes the baby's head becomes very large. Preterm birth is the most common cause hydrocephalus due to an increased risk of bleeding into the brain, which may prevent the absorption of cerebrospinal fluid. Hydrocephalus can also occur in children with birth defects such as spina bifida, in some cases it is inherited, and sometimes it is caused by infections. If the baby is known to have this condition, a caesarean section may be recommended. How seriously ill a child is depends on the cause of the illness. Some children grow up with normal intelligence, others may have serious disabilities, but this cannot be predicted before birth.

376 POSTPARTUM INDEX

How is hydrocephalus diagnosed? During pregnancy, hydrocephalus is determined using ultrasound examination. After birth, head measurements taken on each newborn can reveal the existing condition. Early diagnosis and treatment provide better results.

Treatment

After the baby is born, surgery is usually performed to drain the cerebrospinal fluid through a shunt into the bloodstream. The shunt remains for life. Surgery to insert a temporary shunt may sometimes be performed before birth. A permanent shunt is installed after birth. To treat some forms of hydrocephalus using modern surgical techniques, a hole is made in the skull.

Cerebral (cortical) palsy

The term refers to a group of disorders affecting movement and posture. One in four children have disease-related learning difficulties. The disease may be caused by abnormal brain development before birth, oxygen deprivation, infection, bleeding in the brain, or birth injury. physical symptoms range from muscle weakness and flaccidity to muscle spasticity and immobility.

How is cerebral palsy diagnosed? It is usually not possible to make an accurate diagnosis until the child is one year old, as many parts nervous system up to this point have not yet fully developed. Diagnosis can be made using electroencephalography, computed tomography, as well as vision and hearing tests. In some cases, a blood test is done to evaluate hereditary influences.

Treatment

Cerebral paralysis There is no cure, but there are types of treatment that help minimize the consequences and develop the child’s abilities. These include physical therapy, functional therapy and drug treatment. Surgery is sometimes used to solve problems with deformed limbs.

DISEASES OF THE GINOROGENITAL SYSTEM Urinary obstruction ways

An obstruction occurs when the flow of urine between the kidneys and bladder is partially or completely blocked, leading to hydronephrosis (swelling of the kidneys), which can cause the kidneys to stop working. This disease is detected in the fetus already at the 15th week. Mild hydronephrosis, also known as renopelvic dilatation, may resolve spontaneously towards the end of pregnancy and does not require treatment.

How is urinary tract obstruction diagnosed?

During pregnancy, the disease is determined using ultrasound. In newborns, an ultrasound examination of the kidneys is performed to determine the extent of blockage of the urinary tract. It is possible to conduct other examinations to determine the performance of the kidneys.

Treatment

Surgical intervention in relation to the fetus is performed only in very severe cases, when the disease has covered both kidneys. The operation is effective if done before developing buds not seriously damaged. Immediately after the birth of the child, surgery may be required to remove the obstruction. To combat a urinary tract infection, the child is prescribed antibiotics.

Polycystic kidney disease

When the kidney is poorly connected to the excretory system, this can lead to poor functioning or lack of performance, which is shown by an increase in size and the presence of cysts on an ultrasound scan. A person can live with one functional kidney, but the child does not need kidneys at all for development in the uterus, since the placenta removes decay products. However, once the baby is born, he needs at least one kidney to work. Sometimes the malformation affects only one kidney and the child will not have any serious problems subsequently, while sometimes the poor functioning disappears in childhood. But if the disease affects both kidneys, the amount of fluid around the child will decrease and the lungs will not be able to develop normally. After birth, the baby will have difficulty breathing, and the kidneys will also function poorly. For this reason, bilateral polycystic kidney disease leads to fatal outcome.

A condition called mature polycystic kidney disease, which occurs in adults, also occurs in fetuses. It does not cause any difficulties until the body becomes mature. The disease is usually inherited from one of the parents, although the latter may not be aware of it.

How is polycystic kidney disease diagnosed? During pregnancy, polycystic disease is determined using ultrasound. In newborns, an ultrasound examination of the kidneys is performed, and a computer scan is used to check for the presence of cysts.

Treatment

Depending on the severity of the disease, surgery may be required when the child is older. If the disease is hereditary, additional tests may be required.

Hypospadias

The disease affects approximately one in 300 boys. Hole urethra, which is a tube through which urine is removed from the body and normally located at the end of the penis, opens in another location, usually on the undersurface of the penis. Consequently, problems arise with urination, and the penis may be curved downwards, which, upon reaching puberty, can affect sex life.

How hypospadias is diagnosed

♦ Inability to have normal urine flow.

♦ Curved penis.

♦ Closed foreskin.

Treatment

In very mild cases, no action should be taken. In more serious cases, surgery is necessary to prolong the urethra. Children with hypospadias should not be circumcised, as the foreskin may be used for surgical purposes during surgery.

Undescended testicle

During normal fetal development, the testicles descend through the canal from the abdomen into the scrotum. In some cases, this does not happen before birth; why is not known exactly. This disease is relatively common in premature babies, and much less common in full-term babies. The testicles usually descend at 28 weeks of pregnancy, so if the baby is born before this time, the testicles may not have time to descend. Sometimes only one testicle descends, sometimes the descent does not occur completely.

On What should pay attention

♦ The scrotum appears small or the testicles are of different shapes.

♦ The testicles are not felt in the scrotum.

Treatment

Typically the testicles descend on their own within the first year. Sometimes a testicle that is located in the inguinal canal and has not descended completely can return into place spontaneously. If the testicle does not descend, it may be treated with hormones to help it do so, or surgery may be required.

If the disease is not treated, the child has a high chance of remaining infertile and developing testicular cancer in adulthood.

DIGESTIVE DISEASES

TRACT

Intestinal obstruction

Obstruction can occur anywhere in the intestines, from the esophagus to the anus. A blockage at the top can lead to a buildup of amniotic fluid, which is usually diagnosed during pregnancy. The blockage immediately after the stomach is called duodenal atresia. This type of obstruction is commonly found in children with Down syndrome and will require testing. Blockage in lower parts intestines are not determined before birth.

How obstruction is diagnosed

intestines

To determine the cause of obstruction

Ultrasound examination is used.

Treatment

If there is a blockage, the baby will need surgery after birth to bypass the blockage and allow the baby to feed.

Defects abdominal wall

Defects occur when part of the abdominal wall remains underdeveloped and a hole appears in it. The contents of the abdominal cavity fall out. In some cases, there is a shell that contains the contents. This condition is called omphalocele (fetal hernia) or umbilical hernia, it may be associated with other genetic problems in the child; in this case, an examination is suggested. If the intestines are not closed, the condition is called gastroschisis (a congenital muscle defect in the abdominal wall, usually with a protrusion internal organs, but not in the area of ​​the umbilical ring). The defect is not associated with any developmental problems in the child. If the baby remains healthy, vaginal delivery is possible. Sometimes, if the baby has other abnormalities or the umbilical hernia is too large, a caesarean section is suggested.

How are abdominal wall defects diagnosed?

A child with this defect will most likely be born small, so careful monitoring is required during pregnancy. Abdominal wall defects are usually detected by ultrasound examination.

Treatment

The child requires surgery to correct the defect. Usually one is enough. Sometimes part of the intestine needs to be removed if it is damaged or blocked. Feeding must be introduced gradually and the baby will need quite a long period of time (two to four weeks) before it becomes possible.

Pyloric stenosis

The disease occurs when the pylorus (a ring of muscles that connects duodenum with the stomach) narrows to such an extent that food cannot pass through. Symptoms usually appear between 3-12 weeks.

The disease is more common in boys and is believed to be hereditary.

How is pyloric stenosis diagnosed?

To confirm the diagnosis, physical and ultrasound examinations are performed.

Treatment

The disease is eliminated by a simple surgical operation, in which a small incision is made in the pylorus. After surgery, the child can eat normally and will gain weight quickly.

Diaphragmatic hernia

The diaphragm is a muscle that separates the organs of the abdominal cavity from the organs chest. Early in the development of the fetus in the uterus, there is a hole in the diaphragm that usually closes by the end of the third month. If the opening is left open, the contents of the abdominal cavity, such as the intestines, can end up in the chest cavity and, taking up space there, interfere with the normal development of the lungs and heart.

How is a diaphragmatic hernia diagnosed?

Using ultrasound examination. Children with this condition often have breathing problems after birth.

Treatment

Treatment for a diaphragmatic hernia may require surgery to close the defect in the diaphragm. However, in severe cases, the small size of the lungs does not allow the child to survive. Reliable prediction methods that determine sufficient lung size before birth are not yet available.

After successful surgery to repair a hernia, it is believed that the child will lead normal life. Sometimes a diaphragmatic hernia is associated with genetic diseases, in these cases testing is offered to eliminate the causes.

DISEASES OF THE MUSCULOSCULAR

SYSTEMS

Cleft lip or cleft palate

Defects that are quite common in infants can appear either individually or together. The defect occurs when the fetus's upper lip and/or palate do not meet properly before birth. In many cases the cause of the disease is unknown, although sometimes the defect can be hereditary. If the defect is complex, feeding difficulties arise.

How is a cleft lip or cleft palate diagnosed?

In the majority medical institutions With special ultrasound equipment, these diseases are determined before birth in the second trimester during examination. Otherwise, the defect is detected after birth.

Treatment

A cleft lip can be repaired surgically in a child aged three months. Cleft palate is treated between 6 and 15 months of age. Until this point, a plate is inserted into the baby's palate if feeding problems arise. Plastic surgery gives good results and ensures normal speech development.

Deformed foot

Some children develop a condition called clubfoot. The disease occurs in approximately one child in a thousand. In this case, one or both feet deviate from the normal position. Sometimes the disease is caused by genetic reasons, but more often it appears because the foot was trapped in the uterus, or because its bones did not develop normally.

How is a deformed foot diagnosed?

A standard ultrasound examination will usually reflect any limb defects. With further checks the condition will be clarified.

Treatment

If the cause is limited uterine space, then the only thing needed after birth is physical therapy exercises to straighten the foot. If bones are underdeveloped in childhood, the child will have to undergo surgery.

Spinal diseases

Sometimes part of a vertebra is malformed or missing, causing a curvature of the spine. Sometimes this occurs due to genetic reasons or chromosomal problems. In such cases, it is very difficult to predict what will happen in the long term.

How are diseases diagnosed? spine

Using ultrasound examination.

Treatment

Treatment depends on the severity of the condition. Some children have pronounced scoliosis (curvature of the spine), which can be corrected surgically.

Congenital dislocation hips

Occurs relatively often, due to the fact that an incorrectly formed femoral joint allows the femoral head to jump out of the socket pelvic bone. The cause of hip dislocation is unknown and may be hereditary. The disease occurs ten times more often in girls and more often affects children during the first birth and with breech presentation. Common in twins and may also be associated with congenital conditions such as spina bifida or Down syndrome. The most common dislocation is the left hip, but in 25% both hips are dislocated.

How hip dislocation is diagnosed During a routine newborn examination, the pediatrician flexes the baby's legs in various ways. Clicking could be a sign congenital dislocation hips, then at 6 weeks of age a more thorough examination is carried out to verify the diagnosis. Other symptoms include asymmetrical folds of skin on the top of the legs and the baby's inability to stretch them out, such as when changing a diaper.

Treatment

Early treatment with a fixation device increases the chances of normal development of the hip. When changing a diaper, the device can be easily removed; it does not interfere with feeding, bathing and sleeping. If treatment is required after 6 months, a cast may be used. Very rarely, surgery is required to enlarge the socket in the pelvic bone. It is usually carried out before the child begins to walk.

Hereditary human diseases are studied by medical genetics - a branch of fundamental genetics. Genetics (Greek - genetikos - relating to birth, origin) is a science that studies the patterns of heredity and variability of organisms in general. Medical genetics – This is a branch of human genetics that studies hereditarily determined morphological and functional disorders in human ontogenesis, the patterns of their inheritance, phenotypic implementation and distribution, as well as developing methods for the diagnosis, prevention and treatment of these disorders.

The term "hereditary diseases" is sometimes equated with the term "congenital diseases". Congenital diseases mean conditions that already exist at the birth of a child. Congenital diseases can be caused by hereditary and non-hereditary factors. These include congenital malformations of a non-hereditary nature, which are phenocopies of hereditary malformations. At the same time, not all hereditary diseases are congenital - many diseases manifest themselves at a much later age.

Phenocopy – a non-hereditary change in any characteristics of an organism under the influence of the environment, copying the phenotypic manifestation of mutations that are absent in the genotype of a given individual. For example:

Congenital infections (toxoplasmosis, rubella, syphilis, etc.) can induce phenocopies of pathological mutations in several sibs (sibs are children of the same parental pair: brothers and sisters) and thereby raise suspicion of a hereditary disease.

Phenocopies caused by external factors of a chemical and physical nature can occur with a certain frequency not only in the proband, but also in his siblings, if the factors continue to operate after the birth of a sick child.

The term "family diseases" is not synonymous with "hereditary". Family diseases can be hereditary or non-hereditary. This term only indicates that diseases occur among members of the same family. A family disease can be caused by the same harmful factor that operates in the family: poor lighting, damp apartment, occupational hazard, etc.

Hereditary diseases - These are diseases whose etiological factor is mutations (gene, chromosomal or genomic). On the one hand, most mutations increase the polymorphism of human populations (blood types, hair color, nose shape, etc.), and on the other hand, mutations affect vital important functions and then the disease develops.

Despite the fact that there are no sharp transitions from diseases caused by external factors to hereditary diseases, from a genetic point of view, all diseases, depending on the relative importance of hereditary and environmental factors in their development, are divided by Academician of the Russian Academy of Medical Sciences N.P. Bochkov (1978) into 4 groups:

hereditary diseases. The manifestation of the pathogenic effect of mutation as an etiological factor is practically independent of the external environment. It can only change the severity of the symptoms of the disease. Heredity plays a decisive role here. Diseases in this group include all chromosomal and genetic hereditary diseases with full manifestation: Down's disease, hemophilia, phenylketonuria, achondroplasia, etc. The disease can manifest at any age and not necessarily in childhood (for example, Huntington's chorea develops after 40 years).

Diseases with a hereditary predisposition. For these diseases, heredity is an etiological factor, but for the penetrance of mutated genes, an appropriate state of the body is necessary, due to the harmful influence of the environment (gout, some forms of diabetes - their manifestation depends on excessive nutrition). Such diseases usually appear with age when exposed to external factors: overwork, overeating, cooling, etc.

In this group of diseases, the etiological factors are environmental influences, but the frequency of occurrence and severity of the disease significantly depends on the hereditary predisposition. This group includes atherosclerosis, hypertension, tuberculosis, eczema, and peptic ulcer. They arise under the influence of external factors (sometimes not even one, but a combination of many factors - these are multifactorial diseases), but much more often in individuals with a hereditary predisposition. Like diseases of the 2nd group, they belong to diseases with a hereditary predisposition, and there is no sharp boundary between them.

Heredity does not play any role in the origin of diseases of this group. Etiological factors are only external (environmental) factors. This includes most injuries, infectious diseases, burns, etc. Genetic factors can only influence the course pathological processes(recovery, restoration processes, compensation for impaired functions).

This ranking of diseases into groups is to some extent arbitrary, but it helps to assess the relative importance of heredity and environment in the development of human diseases. Diseases of the 2nd and 3rd groups can be combined into one - these are diseases with a hereditary predisposition.

Hereditary diseases make up a significant part of the structure general pathology person. More than 2000 of them are already known and this list is constantly updated with new forms. They have a significant impact on morbidity and mortality. 40% of child mortality is partially or completely due to hereditary pathology, at least 40% of spontaneous abortions are associated with chromosomal abnormalities.

Most hereditary diseases have a severe chronic course. The state spends enormous amounts of money on servicing patients suffering from hereditary diseases, and if we take into account the great moral damage caused by patients with hereditary pathologies to the family and society, then the need for an organized fight against the spread of hereditary diseases becomes obvious, and, first of all, work on their prevention.

Most gene mutations, and especially chromosomal and genomic ones, cause generalized tissue damage or affect several organs. That is why many hereditary diseases manifest themselves in the form of syndromes and are found in the practice of doctors of any specialty: pediatrician, obstetrician-gynecologist, neurologist, dentist, surgeon, hematologist, endocrinologist, etc.

Hereditary diseases are classified from a clinical and genetic point of view. The basis clinical classification The systemic and organ principle is based, since all hereditary diseases are the same in etiology (they are based on a mutation):

Metabolic diseases - phenylketonuria, galactosemia, gout, glycogenosis, homocystinuria, porphyria, etc.

Connective tissue diseases – Marfan syndrome, chondrodystrophy, achondroplasia, etc.

Blood diseases - hemoglobinopathies, membranopathy, enzymopathies, etc.

Mental illnesses – schizophrenia, manic-depressive psychosis, etc.

Diseases of the gastrointestinal tract – celiac disease, peptic ulcer, hereditary hyperbilirubinemia, etc.

Kidney diseases - hereditary nephritis, cystinuria, cystinosis, polycystic kidney disease, tuberous sclerosis, etc.

Naturally, this classification is conditional. For example, neurofibromatosis (dominant mutation) is found in neurosurgical clinics (brain tumors in patients) and dermatological clinics (patients initially develop large yellowish spots and nodules on the skin). Patients with epilepsy are patients of both neurologists and psychiatrists.

WITH genetic From a point of view, hereditary diseases are classified as mutations, since they are the etiological factor of diseases.

Depending on the level of organization (amount of damage) of hereditary structures, gene, chromosomal and genomic mutations are distinguished, and in this regard, hereditary diseases are divided into 2 large groups:

Genetic - diseases caused by gene mutations that are passed on from generation to generation.

Chromosomal – diseases caused by chromosomal and genomic mutations.

Depending on the genetic approach, hereditary diseases are divided into many groups:

Based on the number of loci involved, hereditary diseases can be:

a) monogenic (one gene is mutated) - phenylketonuria, cystic fibrosis, hemophilia, G-6-FDG deficiency, etc.;

b) polygenic – these are diseases with a hereditary predisposition (hypertension, atherosclerosis, diabetes and etc.). Polygenic diseases are identified in separate group due to the complex nature of the inheritance of the disease and the influence of the environment on the implementation of the predisposition.

Gene mutations can occur in structural and regulatory genes. The bulk of hereditary diseases are obviously caused by mutations in structural genes. There are no well-studied examples of hereditary diseases caused by mutations in regulatory genes yet - even with hemoglobinopathies, metabolic diseases, Ig deficiency. But we are only talking about the assumption of a mutation in the regulatory gene and the search for rigorous evidence.

Based on the nature of inheritance, monogenic diseases are divided into:

a) autosomal dominant, which is based on a violation of the synthesis of structural proteins or proteins that perform specific functions. The effect of the mutant gene is almost 100%. The probability of developing the disease in the offspring is 50%. One of the parents of a sick child (boy or girl) is necessarily sick. Syndactyly, polydactyly, Marfan syndrome, thalassemia, hemorrhagic telangiectasia, neurofibromatosis, elliptocytosis, etc. are inherited by this type;

b) autosomal recessive. With this type of inheritance, the mutant gene appears only in the homozygous state. Affected boys and girls are born with equal frequency. The probability of having a sick child is 25%. Parents may be phenotypically healthy, but are heterozygous carriers of the mutant gene. This type of inheritance includes phenylketonuria, alkaptonuria, albinism and other enzymopathies, defects of the hard palate and upper lip (“cleft palate” and “cleft lip”), myoclonic epilepsy, etc.;

c) recessive inheritance linked to the X chromosome. The effect of the mutant gene is manifested only with the XY set of sex chromosomes, i.e. in boys. The probability of giving birth to a sick boy to a mother who is a carrier of the mutant gene is 50%. The girls are practically healthy, but half of them are carriers of the mutant gene (conductors). Parents are healthy. A sick father does not transmit the disease to his sons (from grandfather to grandson through the mother-conductor). This type of inheritance is associated with hemophilia, myopathy, muscular dystrophy Duchenne, gout, etc.;

d) dominant inheritance linked to the X chromosome. The effect of a dominant mutant gene is manifested in any set of sex chromosomes: XX, XY, XO, etc. The manifestation of the disease does not depend on gender, but is more severe in boys. Among the children of a sick man, in the case of this type of inheritance, all the sons are healthy, and all the daughters are sick. Affected women pass on the altered gene to half of their sons and daughters. This type inheritance can be traced in phosphate diabetes, a hereditary disease in which the reabsorption of phosphorus in the renal tubules is impaired; osteoporosis, osteomalacia, bone deformation, hypophosphatemia are noted.

e) incomplete dominance (semi-dominant type of inheritance). The disease manifests itself in a homozygous state, and in a heterozygous state - under specific conditions (for example, sickle cell anemia will clearly manifest itself as a hemolytic crisis with a decrease in the partial pressure of oxygen in the inhaled air, pneumonia, etc.). The formation of sickle-shaped erythrocytes also increases with an increase in plasma osmolarity, an increase in the content of 2,3-diphosphoglycerate in erythrocytes, a decrease in blood pH, a slowdown in blood flow, and dehydration of the body.

There is obviously no point in dividing gene diseases depending on the nature of the gene mutation (deletion, duplication, substitution), although all these types are established for humans on the basis of a detailed analysis of mutations, since phenotypic manifestation mutation is not determined by the mechanism of its occurrence, but by the type of abnormal peptide - protein, enzyme.

Chromosomal diseases are divided depending on the type of mutation into:

Syndromes caused by numerical anomalies (polyploidy, aneuploidy).

Syndromes caused by structural rearrangements (deletions, inversions, translocations, duplications).

This division of chromosomal diseases helps the doctor in assessing the prognosis for the patient and in medical genetic counseling. Most chromosomal diseases caused by aneuploidy are not transmitted at all, and structural rearrangements (inversions, translocations) are transmitted with additional recombinations that the parents did not have.

If the mutation occurred in germ cells, then we are talking about the so-called complete forms, and if chromosome nondisjunction and structural aberrations arose in the early stages of zygote fragmentation, then mosaic forms develop.

There is another group of diseases associated with heredity - these are diseases that arise when mother and fetus are incompatible with antigens and develop on the basis of an immunological reaction in mothers. The most typical and well-studied disease of this group is hemolytic disease of the newborn. It occurs when an Rh-positive fetus develops in the body of an Rh-negative mother.

How often do we hear: “My grandmother gave me an allergy; she coughed and sneezed all the way,” or “What do you want from Vasya, his father did not dry out. Bad heredity..." Is it true that most of the so-called terrible diseases are inherited? Should you be afraid to give birth if your aunt is schizophrenic? What are congenital diseases and is it possible to live with them? Let's figure it out together!

Congenital diseases

With them a person is born. Sometimes they declare themselves immediately, from the first days of life, sometimes they wake up after many, many years. Some congenital diseases are caused by microbes. Congenital syphilis, AIDS, tuberculosis, sick parents infect their children with this nasty thing. Others arise due to harmful effects on the fetus during pregnancy. For example, disorders of the nervous system in a newborn due to drunken conception, or jaundice and liver damage due to Rh conflict between mother and child.

Sometimes no reason can be identified at all: the parents are healthy, do not drink or smoke, but the baby has a congenital heart defect. Or the nightmare of women who give birth late, Down syndrome (a combination of a mental defect and a specific Mongoloid appearance) is also congenital: the embryo’s chromosomes were incorrectly divided immediately after conception.

Congenital diseases are not inherited. Even if some chromosome is “broken,” this is an isolated case and the children of a sick person will not inherit the “breakage.”

What will save you

It is the duty of parents to take care of their children. A month before the expected act of conception, we stop drinking, smoking, treat all our chronic diseases, including sexually transmitted diseases, and take vitamins. A pregnant mother registers as early as possible and follows all the doctor’s instructions.

Hereditary diseases

It’s as if they are attached to genes and pass along with them from parents to children. However, getting a “sick gene” does not mean getting sick. For a hereditary disease to manifest itself, a couple of dozen defective genes must meet, and such a fatal coincidence happens quite rarely. It is more correct to say that we do not inherit a disease, but only the RISK OF GETTING ILL.

It is curious that diabetes mellitus is most often inherited directly: from grandmother to mother and her son. And schizophrenia diagonally: from aunt to nephew. Very heavy hereditary diseases are extremely rare, since carriers of these genetic defects, sad as it may be, they die before they leave offspring.

How to escape

In the most specific way: if the father has diabetes, do not feed the child semolina porridge, buns and chocolates; let him eat healthy food: meat, vegetables, fruits, oatmeal, rye bread and exercise to lower blood sugar levels. Your daughter's aunt and your sister haven't left the psychiatric hospital for months? Then don't give your girl to kindergarten, do not invite a nanny, raise her at home, caress her without measure, protect her fragile psyche from the trauma of separation.

Feel free to seek advice from a geneticist, and he will tell you whether the disease that worries you is hereditary, as well as how likely it is to pass it on to your children.

"Acquired" diseases

For development, they need a combination of several factors: a weak point in the body and the harmful influence of the environment. That is, if a person lives in favorable conditions suitable for him, then he does not get sick. But as soon as his lifestyle becomes unhealthy, he immediately “catch” the disease. For example, to develop a stomach ulcer, it is not enough to pick up specific bacteria; you also need to get stuck in chronic stress, blame yourself for all mortal sins, and chew and scold yourself. And then the body’s defenses will decrease, the work of a weak person from birth digestive tract will be completely disrupted, the bacteria will take up their dirty work and create an ulcer in the wall of the stomach.

The vast majority of diseases are acquired and bronchial asthma, And multiple sclerosis, And hypertonic disease, and spinal spondylosis. All of them are not contagious and are not transmitted directly from parents to children. But weak spots we often inherit along with our physique and character. For example, peptic ulcer People who are punctual, anxious, thin, and taller than average are somewhat more likely to get sick; and gallstones are hot-tempered, short, plump and stocky.

What will save you

Having studied the illnesses of relatives and looked at myself in the mirror, “Who do I look like?” It won’t be much of a problem to live in such a way that you don’t catch everything that mom and dad suffered from. Read books about healthy image life, pick up effective ways combat stress, and most importantly, do not forget to apply this extensive theoretical knowledge in practice!

Why there is confusion

Sometimes hereditary diseases are called “congenital”, which reflects the single fact that the baby was born with them. Or they talk about acquired diseases as “inherited from your parents,” meaning: “You look like them, you live like them and you get sick from the same things.” When a doctor talks about a “genetic disease,” he means that the disease is associated with a disorder in the genes, and nothing more. To avoid confusion, always meticulously ask the doctor what meaning he means by this or that term.

Federal Agency for Health and Social Development

GOU VPO "Rostov State medical University Federal Agency for Health and Social Development"

COURSE WORK

"Congenital diseases. Phenocopying and its causes"

Rostov-on-Don

INTRODUCTION

1. CONGENITAL DISEASES

2. ROLE OF HEREDITARY AND CONSTITUTION IN PATHOLOGY

3. PHENOCOPIES AND MECHANISMS OF THEIR APPEARANCE

4. ANTENATAL PATHOLOGY

5. DISORDERS OF EMBRYONAL DEVELOPMENT

6. DRUG THERAPY FOR SOMATIC DISEASES IN PREGNANT WOMEN

CONCLUSION

LIST OF USED LITERATURE

INTRODUCTION

There is a saying: “We all stand on the shoulders of our ancestors.” This statement is true not only in relation to cultural level, family traditions and upbringing. Babies carry genetic information from all previous generations and, unfortunately, not always useful. Therefore, future parents need to know everything about hereditary diseases.

Those diseases are called hereditary, the only cause of which was a “breakdown”, i.e. gene mutation. A hereditary predisposition can also manifest itself with age: in order for a defective gene to “come to life”, a certain combination of external factors must push it to do so.

Congenital diseases are caused by various harmful factors that affect the expectant mother during pregnancy. Chromosomal diseases occur from disruption of the structure of many genes and chromosomes.

Multifactorial diseases (diseases that have several causes) appear if children with a certain type immune system(primarily abnormal) viruses, bacteria, protozoa, toxic and drugs act.

As a rule, hereditary diseases manifest themselves only as malformations of various organs and developmental delays. Chromosomal defects are much more serious problem, because they cause severe intellectual defects, such as Down syndrome.

Many hereditary diseases make their debut in childhood, although in practice they can be detected many years later. They are very diverse; more precisely, each disease has its own genetic basis.

Diseases are transmitted directly from parents to children, but in this case the fetus dies before birth. More often, inheritance occurs differently: only children who received the defective gene from both parents are affected. If a child gets different genes from his parents - one healthy, the other sick, then the disease will not manifest itself in any way. The probability of having a sick child from parents who have both a healthy and a sick gene is 25%.

According to statistics, 2.4% of newborns have hereditary disorders. You can prevent the birth of children with chromosomal diseases if you give birth to them on time. For example, the risk of having a child with Down syndrome for a woman increases from age 35 and reaches 1% by age 39.

The purpose of this work is to study congenital diseases, phenocopying and the causes of occurrence.

In accordance with specified purpose The following tasks have been set:

Explore general characteristics congenital diseases;

Study the role of heredity and constitution in pathology, as well as the forms of antenatal pathology;

Study hereditary predisposition to diseases and treatment methods;

Study phenocopying and the reasons for its occurrence;

To study drug therapy for somatic diseases in pregnant women;

Analyze the relevance of the topic under study, as well as methods for preventing congenital diseases.

To achieve the set goal and solve the assigned problems, this work used scientific and educational literature, as well as information resources on the Internet.

This problem is long-standing and very serious, although no more than five percent of newborn children suffer from hereditary diseases.

Hereditary diseases are the result of a defect in the genetic apparatus of cells passed from parents to children and are already present during the intrauterine development of the fetus. Hereditary form may have diseases such as cancer, diabetes, heart defects and many other diseases. Congenital diseases may result from abnormal development of genes or chromosomes. Sometimes it only takes a few abnormal cells to appear for a person to subsequently develop a malignant disease.

Hereditary and congenital diseases in children

Concerning medical term « genetic diseases"then it applies to those cases. When the moment of damage to the cells of the body occurs already at the stage of fertilization. Such diseases arise, among other things, due to a violation of the number and structure of chromosomes. This destructive phenomenon occurs as a result of improper maturation of the egg and sperm. These diseases are sometimes called chromosomal. These include such serious illnesses as Down syndrome, Klinefelter syndrome, Edwards syndrome and others. Modern medicine almost 4 thousand are known various diseases arising on the basis of genetic abnormalities. Another interesting fact is that 5 percent of people have at least one defective gene in their bodies, but are completely healthy people.

Terminology in the article

A gene is the initial unit of heredity, which is part of a DNA molecule that influences the formation of protein in the body, and therefore the signs of the state of the body. Genes are presented in binary form, that is, one half is transmitted from the mother, and the other from the father.

Deoxyribonucleic acid (DNA) is a substance found in every cell. It carries all the information about the state and development of a living organism, be it a person, an animal or even an insect.

Genotype is a set of genes acquired from parents.

Phenotype - set characteristic features state of the body during its development.

Mutations are persistent and irreversible changes in the genetic information of an organism.

Quite common are monogenic diseases, in which only one gene responsible for a certain function of the body is damaged. Due to the fact that there are many such diseases, a certain classification has been adopted in medicine, which looks like this.

Autosomal dominant diseases.

This group includes diseases that occur when there is only one copy of a defective gene. That is, only one of the patient’s parents is sick. Thus, it becomes clear that the offspring of such a sick person have a 50% chance of inheriting the disease. This group of diseases includes diseases such as Marfan syndrome, Huntington's disease and others.

Autosomal recessive diseases.

This group includes diseases that occur due to the presence of two defective copies of a gene. In this case, those who gave birth to a sick child can be absolutely healthy, but at the same time be carriers of one copy of a defective, mutated gene. In such a situation, the risk of having a sick child is 25%. This group of diseases includes diseases such as cystic fibrosis, sickle cell anemia and other ailments. Such carriers usually appear in closed societies, as well as in the case of related marriages.

X-linked dominant diseases.

This group includes diseases that occur due to the presence of defective genes on the female sex X chromosome. Boys are more likely to suffer from such diseases than girls. Although a boy born from a sick father may not pass the disease on to his offspring. As for girls, they will all necessarily have a defective gene. If the mother is sick, then the probability of inheriting her disease is the same for boys and girls and is 50%.

X-linked recessive diseases.

This group includes those diseases that are caused by mutations of genes located on the X chromosome. In this case, boys are at greater risk of inheriting the disease than girls. Also, a sick boy may not subsequently pass the disease on to his children. Girls will also have one copy of the defective gene in any case. If a mother is a carrier of a defective gene, then she has a 50% chance of giving birth to a sick son or a daughter who will become a carrier of such a gene. This group of diseases includes diseases such as hemophilia A, Duchenne muscular dystrophy and others.

Multifactorial or polygenic genetic diseases.

This includes those diseases that arise as a result of a malfunction of several genes at once, and under the influence external conditions. The heredity of these diseases is manifested only relatively, although the diseases often have familial characteristics. These are diabetes, heart disease and some others.

Chromosomal diseases.

This includes those diseases that occur due to a violation of the number and structure of chromosomes. If such signs are present, women often experience miscarriages and undeveloped pregnancies. Children of such women are born with both mental and physical abnormalities. Such cases, alas, occur quite often, namely in one out of twelve fertilizations. The results of such sad statistics are not visible due to termination of pregnancy at a certain stage of fetal development. As for born children, statistics say that one out of one hundred and fifty newborns is born with this disease. Already in the first trimester of pregnancy, half of women with chromosomal diseases of the fetus experience miscarriages. This indicates that the treatment is ineffective.

Before talking about the prevention of hereditary and congenital diseases, it is worth spending a little time on issues related to polygenic or multifactorial diseases. These diseases occur in adults and often cause concern about the feasibility of having offspring and the likelihood of diseases passing on from parents to children. The most common diseases in this group are such diseases.

Diabetes mellitus types 1 and 2 .

This disease has partially hereditary characteristics. Type 1 diabetes can also develop due to a viral infection or due to long-term nervous disorders. Examples have been noted where diabetes-1 arose as a result of allergic reaction to aggressive external environment and even on medical supplies. Some people with diabetes are carriers of a gene that is responsible for the likelihood of developing the disease in childhood or adolescence. As for type 2 diabetes, the hereditary nature of its occurrence is clearly visible. The most high probability develop type 2 diabetes in the first generation of the carrier's descendants. That is, his own children. This probability is 25%. However, if the husband and wife are also relatives, then their children will necessarily inherit parental diabetes. The same fate awaits identical twins, even if their diabetic parents are not related.

Arterial hypertension.

This disease is the most typical of the category of complex polygenic diseases. In 30% of cases of its occurrence, there is a genetic component. As arterial hypertension develops, at least fifty genes take part in the disease and their number grows over time. The abnormal effect of genes on the body occurs under the influence of environmental conditions and the body’s behavioral reactions to them. In other words, despite the body’s hereditary predisposition to the disease arterial hypertension, a healthy lifestyle plays a huge role in treatment.

Violation fat metabolism.

This disease is the result of the influence of genetic factors together with a person’s lifestyle. Many genes are responsible for the metabolism in the body, for the formation of fat mass and for the strength of a person's appetite. Failure in the work of only one of them can lead to the appearance of various diseases. Externally, a disorder of fat metabolism manifests itself in the form of obesity in the patient’s body. Among obese people, fat metabolism is impaired in only 5% of them. This phenomenon can be massively observed in some ethnic groups, which confirms the genetic origin of this disease.

Malignant neoplasms.

Cancer tumors do not appear as a result of heredity, but haphazardly and, one might even say, by accident. Nevertheless, isolated cases have been recorded in medicine when cancerous tumors arose precisely as a result of heredity. These are mainly cancers of the breast, ovaries, colon and blood. The reason for this is a congenital mutation of the VYACA1 gene.

Violation mental development.

The most common cause of mental retardation is hereditary factor. Parents of a mentally retarded child are often carriers of a number of mutant genes. Often, the interaction of individual genes is disrupted or disturbances in the number and structure of chromosomes are observed. Characteristic symptoms include Down syndrome, fragile X syndrome and phenylketonuria.

Autism.

This disease is associated with impaired brain functionality. It is characterized by poorly developed analytical thinking, stereotypical behavior of the patient and his inability to adapt to society. The disease is detected by the age of three years of a child’s life. Doctors associate the development of this disease with improper synthesis of proteins in the brain due to the presence of gene mutations in the body.

Prevention of congenital and hereditary diseases

It is customary to divide preventive measures against such diseases into two categories. These are primary and secondary measures.

The first category includes such measures as identifying the risk of disease at the stage of planning conception. It also includes measures for diagnosing fetal development using systematic examinations of a pregnant woman.

When planning a pregnancy, in order to prevent hereditary diseases, it is worth contacting the regional clinic, where the “Family and Marriage” database stores archival data on the health of the spouses’ ancestors. As for medical genetic consultation, it is necessary if the spouses have chromosomal changes, hereditary diseases, and, of course, if abnormal development of the fetus or an already born child is detected. In addition, such consultation must be obtained if the husband and wife are in family ties. Consultation is extremely necessary for those couples who have previously experienced miscarriages or children who were stillborn. It will also be useful for all women who will give birth for the first time at the age of 35 or more.

At this stage, a study is made of the pedigree of both spouses, based on the medical data available in the archive on the health of previous generations of the husband and wife. In this case, it is possible to identify with almost absolute accuracy whether there is a likelihood of a hereditary disease occurring in the unborn child, or whether there is none. Before going for a consultation, spouses must ask their parents and relatives in as much detail as possible about the diseases that occurred in previous generations of the family. If there are hereditary diseases in the family history, then you must tell your doctor about it. This will make it easier for him to determine the necessary preventive measures.

Sometimes at the stage primary prevention it is necessary to analyze the state of the chromosome set. This analysis is performed on both parents, since the child will inherit half of the chromosome from mom and dad. Unfortunately completely healthy people may be carriers of balanced chromosomal rearrangements and not even suspect the presence of such a deviation in their bodies. If a child inherits a chromosomal rearrangement from one of the parents, then the likelihood of serious illnesses will be quite high.

Practice shows that in such a family the risk of having a child with a balanced chromosomal rearrangement is about 30%. If spouses have changes in their chromosome set, during pregnancy, PD can prevent the birth of an unhealthy child.

As part of the primary prevention of the occurrence congenital anomalies nervous system of a child, such a method as the appointment of folic acid, which is a solution of vitamins in water, is widely used. Before pregnancy, a sufficient amount of folic acid enters the body of a woman in the process good nutrition. If she adheres to any diet, then, of course, the intake of acid may not be in the amount that the body requires. In pregnant women, the body's need for folic acid increases by one and a half times. It is not possible to ensure such an increase through diet alone.

By the way, this is the only vitamin that during pregnancy should enter the body in greater quantities than before pregnancy. It is possible to satisfy the pregnant woman’s body’s need for folic acid only through its additional use. Folic acid has unique properties. So, additional intake of this vitamin two months before conception and during the first two months of pregnancy reduces the likelihood of abnormal abnormalities in the child’s central nervous system by three times! Usually the doctor prescribes four standard tablets per day. If the first child had some kind of deviation in the development of the central nervous system, and the woman decided to give birth again, then in this case she needs to increase the amount of folic acid taken by two, or even two and a half times.

Secondary prevention of congenital and hereditary diseases

This includes preventive measures that are applied even in the case when it is known for sure that the fetus in the body of a pregnant woman develops with pathological deviations from the norm. If such a sad circumstance is discovered, the doctor must inform both parents about this and recommend certain procedures to correct the development of the fetus. The doctor must explain exactly how the child will be born and what awaits him as he grows up. After this, the parents decide for themselves whether it is worth giving birth to a child or whether it would be better and more humane to terminate the pregnancy in time.

Two methods are used to diagnose the condition of the fetus. These are non-invasive measures that do not require physical intervention and invasive measures in which a sample of fetal tissue is taken. The essence of non-invasive measures is to test the mother's blood and ultrasound diagnostics her body and that of the fetus. Recently, doctors have mastered the technology of taking blood tests from the fetus. The sample is taken from the mother's placenta, into which fetal blood penetrates. This process is quite complicated, but also quite effective.

Maternal blood testing is usually done at the end of the first - beginning of the second trimester of pregnancy. If two or three substances are present in the blood in abnormal quantities, then this may be a sign of the presence of a hereditary disease. In addition, at the end of the first trimester of pregnancy, the mother is determined human chorionic gonadotropin person. This is a pregnancy hormone, which in a woman’s body is produced by the placenta and in turn produces serum protein A. In the second trimester of pregnancy, an analysis is done for the content of hCG, alpha-fetoprotein, and unbound (free) estriol.

A set of such measures in world medicine is called a “triple panel”, and the overall technique is called “biochemical screening”.

During the first trimester of pregnancy, the concentration of hCG in the blood serum doubles daily. After that full formation placenta, this indicator stabilizes and remains unchanged until birth. HCG supports the production in the ovaries of hormones necessary for the normal course of pregnancy. In the mother’s blood, not the entire hormone molecule is determined, but only the p-subunit. If the fetus has chromosomal diseases, in particular Down's syndrome, the content of the hormone in the mother's blood serum is significantly overestimated.

Whey protein A is produced in the mother's body in the tissue of the placenta. If the fetus has a chromosomal disease, then the amount of protein will be underestimated. It should be noted that such changes can only be recorded from the tenth to the fourteenth week of pregnancy. In the subsequent time, the level of protein in the blood serum of the mother returns to normal.

Alpha fetoprotein (AFP) is produced already in the tissues of the embryo and continues in the tissues of the fetus. The function of this component is not fully understood. It is determined in a woman’s blood serum or amniotic fluid as a marker of congenital defects of the central nervous system, kidneys, or anterior abdominal wall. It is known that when oncological diseases this protein is found in the blood serum of both adults and children. As the fetus develops, this protein passes from the fetal kidneys into the mother's blood through the placenta. The nature of the change in its amount in the mother’s serum depends both on the presence of a chromosomal disease in the fetus and on some features of the course of the pregnancy itself. Thus, the analysis of AFP without assessing the functionality of the placenta is not of decisive importance from the point of view of diagnostic accuracy. Nevertheless, AFP as a biochemical marker of congenital diseases has been well studied.

AFP is most accurately determined during the second trimester of pregnancy, namely between the sixteenth and eighteenth weeks. Until this time, from the point of view of diagnostic accuracy, it makes no sense to determine this protein. If the fetus has a congenital defect of the central nervous system or the anterior abdominal wall, then the level of AFP in the mother's blood serum will be significantly higher than normal. If the fetus suffers from Down or Edwards syndrome, then, on the contrary, this indicator will be lower than normal.

The hormone estriol is produced by both the maternal placenta and the fetus itself. This hormone ensures the normal course of pregnancy. The level of this hormone in the mother's blood serum during normal conditions also increases progressively. If the fetus has a chromosomal disease, then the level of unbound estriol in the mother’s body is significantly lower than the norm during normal pregnancy. Studying the level of the hormone estriol allows one to determine with sufficient accuracy the likelihood of having a child with a hereditary disease. However, the results of the analysis can only be interpreted experienced specialists, because this process is quite complex.

Carrying out biochemical screening is very important procedure. In addition, this method has a number of advantages. He does not demand surgical intervention into the mother's body and is not technologically complex process. At the same time, the effectiveness of this study is very high. However, this method is not without its drawback. In particular, it allows you to determine only the degree of probability of the occurrence of a congenital disease, and not the fact of its presence. In order to accurately identify this presence, additional diagnostic testing is required. The saddest thing is that the results of biochemical screening can be absolutely normal, but the fetus has a chromosomal disease. This technique requires the most accurate determination of the date of fertilization and is not suitable for studying multiple pregnancies.

Ultrasonography

Devices for ultrasound diagnostics are constantly being improved. Modern models allow you to consider the fetus even in the format of a three-dimensional image. These devices have been used in medicine for quite a long time and during this time it has been fully proven that they do not have any effect. negative impact neither on the health of the fetus, nor on the health of the mother. According to the medical regulations in force in Russian Federation, ultrasound examination of pregnant women is carried out three times. The first time this is done during the period 10 - 14 weeks of pregnancy, the second 20 - 24 and the third 32 - 34 weeks. The first study determines the duration of pregnancy, the nature of its course, the number of fetuses and describes in detail the condition of the mother’s placenta.

Using an ultrasound, the doctor determines the thickness of the collar space along the back surface of the fetal neck. If the thickness of this part of the fetal body is increased by three or more millimeters, then in this case there is a possibility that the child will develop chromosomal diseases, including Down syndrome. In this case, the woman is assigned additional examination. At this stage of pregnancy, the doctor checks the degree of development of the fetus's nasal bone. If the fetus has a chromosomal disease, the nasal bone will be underdeveloped. With this detection, additional examination of the mother and fetus is also required.

During the second study, at 10-24 weeks of pregnancy, the fetus is examined in detail for the presence of developmental defects and signs of chromosomal diseases. The condition of the placenta, cervix and amniotic fluid is also assessed.

Almost half of fetal malformations can be detected during ultrasound examination during the period 20 - 24 weeks of pregnancy. Moreover, the remaining half may in fact not be detected at all by any of the currently known diagnostics. Thus, it is impossible to say that diagnostics can one hundred percent determine the presence of a congenital disease in a fetus. Nevertheless, it is necessary to do it, at least for the sake of that half of the cases that are determined with accuracy.

It is understandable that parents are impatient to find out who will be born to them, a girl or a boy. It should be said that conducting research just for the sake of curiosity is not recommended, especially since in five percent of cases it is not possible to accurately determine the sex of the child.

Very often, the doctor prescribes repeated examinations for pregnant women, and this scares many. However, there is no need to panic because only 15% of repeat examinations are associated with the presence of signs of abnormal fetal development. Of course, in this case, the doctor must tell both parents about this. In other cases, repeated examination is associated either with a safety net or with the peculiarity of the location of the fetus.

At the stage of pregnancy at 32-34 weeks, the research process determines the rate of fetal development and identifies signs of defects that are characteristic of late manifestation. If any pathology is detected, the pregnant woman is asked to have a tissue sample of the fetus or placenta analyzed.

Chorionic villus (placenta) biopsy can be done between 8 and 12 weeks of pregnancy. This procedure is performed on an outpatient basis. No more than five to ten milligrams of tissue is taken for analysis. Such an insignificant amount is quite enough to analyze the number and structure of chromosomes. This method makes it possible to accurately determine the presence or absence of a chromosomal disease.

Amniocentesis is a technique for taking amniotic fluid for analysis. They begin to be produced in the body of a pregnant woman soon after conception. The amniotic fluid contains fetal cells. During analysis, these cells can be isolated and examined. Typically, this test is performed between 16 and 20 weeks of pregnancy. In this case, no more than 20 milliliters of water is taken, which is absolutely safe for the woman and the fetus. Another method of “early amniocentesis” is also used, which can be performed at the end of the first trimester of pregnancy. Recently, it has been rarely used. This is due to the fact that in last years cases of malformation of the limbs in the fetus have become more frequent.

Cordocentesis is another name for intrauterine umbilical cord puncture. This technique is used to obtain a fetal blood sample for further laboratory testing. Such an analysis is usually carried out between the 20th and 24th weeks of pregnancy. The amount of blood required for a full analysis is about three to five grams.

It should be said that all of the above methods are, to a certain extent, fraught with unpleasant consequences. In particular, statistics show that after such studies, one to two percent of women have a termination of pregnancy. Thus, these tests are best performed when the likelihood of congenital diseases in the fetus is too high. At the same time, the importance of these tests cannot be denied, since they make it possible to identify even one altered gene in the fetal body. And yet, invasive methods are gradually becoming a thing of the past, and they are being replaced by new technologies. They allow the isolation of fetal cells from the mother's blood.

Thanks to the development of a method such as in vitro fertilization in the treatment of infertility, it has become possible to carry out preimplantation diagnostics. Its essence is as follows. The egg is artificially fertilized in laboratory conditions and placed for a certain time in the incubator. Here cell division occurs, that is, the formation of an embryo essentially begins. It is at this time that you can take one cell for research and conduct a full DNA analysis. In this way, it is possible to find out exactly how the fetus will subsequently develop, including from the perspective of the likelihood of hereditary diseases.

At the end of the article, it should be emphasized that the main goal of all these studies is not only to identify the presence or absence of a hereditary disease in the fetus, but also to promptly warn parents and sometimes relatives of the unborn baby about this. It often happens that there is no hope for correction of any pathology identified in the fetus’s body, just as there is no hope that the born child will be able to develop normally. In such a tragic situation, doctors recommend that parents artificially terminate the pregnancy, although the final decision on this matter is made by the parents. However, they need to take into account that the tragedy of termination of pregnancy is not commensurate with the tragedy that will happen at the birth of a defective child.