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Can a child with Down syndrome be born to relatively healthy parents who, according to all the rules, planned a pregnancy in advance? Doctors say that this is a purely genetic accident. The reasons for the birth of children with Down syndrome were identified only from the statistics of such cases in medical practice, the theoretical analysis of genetic scientists and the history of genetic examinations of "sunny" children. Why are babies born with Down syndrome? When can an anomaly be discovered? Are there ways to prevent the syndrome?
Why are babies born with Down syndrome?
From the point of view of physiology, pathology appears during cell division after conception. The egg cell begins to actively divide, not yet moving through the fallopian tubes. By the time it is attached to the uterine cavity (so-called implantation), it already becomes an embryo. If a child has Down syndrome, then this will be clear almost immediately after conception, but it is still impossible to diagnose a genetic pathology so early.
"Sunny" babies appear for the reason that one extra chromosome appears in the genetic material of the mother or father. In most cases (90%) the embryo receives 24 chromosome from the mother, but it happens (10%) that it is from the father. In some cases (almost 6%), pathology is associated with the presence of not a whole extra chromosome, but only its fragments.
This is how doctors answer the question of why children with Down syndrome are born. The causes and factors provoking genetic pathology may be different, and the above process is described only from a physiological point of view.
What kind of "solar" disease can be?
There are several forms of Down's disease. Trisomy is the most common case. Trisomy is a pathology in which one of the sex cells of the parents contains an extra 24 chromosome (normally, the child receives 23 chromosomes from the father and the same amount from the mother). Merging into a second cell, an egg or sperm cell forms a gamete with 47 chromosomes together 46.
There is a so-called "familial" syndrome. In this case, the birth of a “special” child is due to the fact that there is a so-called Robertsonian translocation in the karyotype of one of the parents. This is what doctors call the long arm of chromosome 21, which, in the process of cell union and division, causes trisomy.
The mildest form of "solar" disease is mosaicism. Genetic pathology develops in the embryonic period due to nondisjunction of chromosomes during cell division. In this case, the violation occurs only in individual organs or tissues, with trisomy, the anomaly is borne by all the cells of the little man's body.
How does a mother's age affect the risk of having a baby with Down's disease?
Why are babies born with Down syndrome? Doctors have several opinions on this matter. The most common reason is the age of the expectant mother. The older the mother, the greater the risk of having a baby with any abnormalities. At the age of twenty-five, the probability of conceiving a defective baby is less than one tenth of a percent, and by the age of 40 it reaches five percent. According to medical statistics, 49-year-old mothers have one child with Down syndrome in every twelve cases.
In reality, the majority (almost 80%) of "sunny" babies are born to young mothers under the age of 30. This is because older women tend to give birth less often. So, the reasons for the appearance of children with Down's disease in these cases are different.
And the father's age?
For men, the risk of conceiving a special child increases only after 42-45 years. This is usually associated with age-related decline in sperm quality. The likelihood of conceiving a "sunny" baby is also influenced by genetic abnormalities in the cells of both the father and the mother. Some of them are not a congenital phenomenon, but an age-related change. Sometimes there are cases when there are forty-five chromosomes in the cells of the spouses - then the risk of pathology increases.
What genetic causes are risk factors?
The risk of having a baby with Down syndrome is higher if the parent's cells contain similar genetic information. Often "solar" children are born with closely related relationships, but it rarely happens that similar material is contained in the cells of parents who are in no way related to blood.
The birth of a child with Down syndrome is also likely if there are genetic diseases, unfavorable heredity and predisposition in the pedigree. There is a risk if the mother has diabetes, epilepsy, or has an unfavorable history: miscarriages in previous pregnancies, stillbirths, or infant deaths.
Does lifestyle influence the risk of having a "sunny" baby?
Why might a baby with Down syndrome be born? Doctors say that the lifestyle of future parents does not affect this in any way. However, another indication of a more attentive attitude towards the expectant mother at the first screening will be the fact of long-term work in hazardous production. Unfortunately, it is rarely possible to find out exactly what caused the conception of a "sunny" baby, so statistics cannot be given here.
In addition, in some cases, children with Down syndrome (we study the causes of the pathology throughout the article) are born due to abnormalities in the development of pregnancy. True, this can rather be attributed to genetic reasons.
What is a folate cycle disorder?
Most likely, it is the violation of the folate cycle that is the reason for the birth of babies with Down's disease in young and relatively healthy mothers. What is meant by this phrase, why are children born with Down syndrome? The reasons may lie in impaired absorption of folic acid (it is also vitamin B9).
Doctors must prescribe folic acid intake for both those who are already in position and those who are just planning a pregnancy. B9 is prescribed for a reason - a lack of an element can cause not only Down's syndrome, in which chromosomes do not diverge, but also other pathologies of embryonic development.
Why vitamin B9 is not absorbed? Three genes, also called folate cycle genes, are responsible for this. Sometimes they "do not work at full capacity" and instead of 100%, the body absorbs at best 30% of folic acid. Women in whom the vitamin is not fully absorbed should take an increased dosage of folic acid and more often eat foods enriched with B9. You can find out if there is a violation of the folate cycle by doing a genetic test.
Lack of vitamin B9 can cause digestive problems that interfere with the absorption of nutrients.
Have you done any more research?
The above are the reasons why babies with Down syndrome are born. But medicine does not stand still. Recent studies allow us to identify two more factors that theoretically can influence the likelihood of the birth of "sunny" babies.
Indian scientists have found that not only the age of the mother herself, but also the age of the maternal grandmother can become a risk factor. The older the grandmother was when she gave birth to her daughter, the higher the likelihood that she will give birth to her grandson or granddaughter with Down's disease. The risk increases by 30% with each “missed” year by the grandmother after 30-35 years.
Another assumption, made by scientists after recent studies of the issue, suggests that increased solar activity can affect the onset of pathology. So, according to the observations of medical scientists and geneticists, often the conception of such children occurred after a surge in the activity of the sun.
What do psychologists and esotericists say about the reasons for the birth of "solar" children?
Why are babies born with Down syndrome? Parapsychologists answer this question by referring to karmic debts. They say that in every family there should appear the person who is intended. And if the parents were really looking forward to the boy, and a girl appeared, then it is likely that she will subsequently have a baby with Down's disease. If, in adulthood, a woman decides to have an abortion, when it turns out that there is a genetic anomaly, then the unhealthy karma will pass to other children who will be born in this family.
By the way, according to ancient legend, which is also confirmed by modern esotericists, "solar" children are the reincarnated souls of sages and healers who in past life distinguished by pride. For this, they were placed in a shell that makes other people wary, but in return they were endowed with a deep understanding of the world.
How is a genetic disorder diagnosed?
Early diagnosis of pathology is available today. In the early stages of pregnancy, ultrasound diagnostics and biochemical screening are used. The material for the study is the shell of the embryo or amniotic fluid. The latter method is quite risky, there is a possibility of damage to the placenta (with all the negative consequences) or spontaneous abortion. That is why the analysis of amniotic fluid and biopsy are carried out exclusively according to indications.
After birth, it is not difficult to diagnose pathology. How are babies born with Down syndrome born? Such babies weigh less than usual, their eyes are Mongoloid, the bridge of the nose is too flat, and the mouth is almost always ajar. Often "sunny" children have a number of concomitant diseases, but not always mental disorders.
What do parents do when they find out that a child has a genetic disease?
Down syndrome can be diagnosed in early pregnancy, when termination is possible with little or no harm to the health of the expectant mother. This is what women in Russia do most often. Still, raising a "sunny" child requires a lot of strength, mental balance, time and money. Such babies need much more parental attention and care, so women who have been diagnosed with a genetic fetal abnormality cannot be judged.
More than 90% of women terminated pregnancy when it was found that the fetus has Down syndrome. Parents leave about 84% of newborns with this genetic disease in maternity hospitals, abandoning them. In most cases, the medical staff only supports this.
And what about other countries?
European mothers had an abortion in 93% of cases if doctors diagnosed a genetic abnormality (2002 data). The majority of families (85%), in which a "sunny" baby appears, abandon the child. It is indicative that in the Scandinavian countries there is not a single case of refusal of such children, and in the USA more than two hundred and fifty married couples are in line for their adoption.
Who leaves the special child?
Of course, some families leave the child behind. Children of celebrities with Down syndrome are known. A special baby is being raised by Evelina Bledans, coach of the Spanish football team Vicente del Bosque, Lolita Milyavskaya (first doctors diagnosed Down syndrome, but then changed the diagnosis to autism), daughter of the first Russian president Tatyana Yumasheva.
"Sunny" babies develop more slowly than their peers. They are shorter, lagging behind in physical development, often have poor vision and hearing, are overweight, and often have congenital heart defects. It is believed that children with pathology are not capable of learning, but this is not so. If you regularly deal with such a baby and pay attention to him, then he will be able to take care of himself and even perform more complex actions.
How are children with the syndrome treated and adapted to society?
It is impossible to completely cure the genetic anomaly, but regular medical supervision and systematic training in special programs will help the "sunny" baby to acquire basic self-care skills and even subsequently get a profession, and then create a family of his own.
Classes with down children can be conducted both at home and in special rehabilitation centers, in kindergartens and schools. It is necessary to instill in the child self-service skills, teach writing, counting, develop memory and perception, and socially adapt. Speech therapy massage, breathing exercises, exercises for the development of motor skills, developmental games, physiotherapy, animal therapy are useful for "sunny" children. You also need to treat associated pathologies.
Are there methods to prevent Down syndrome?
To prevent the risk of developing Down's disease, it is necessary to be examined by medical specialists while planning pregnancy. It is advisable to do a genetic test to determine if there are disorders in the absorption of folic acid, to visit a gastroenterologist if there is a suspicion of insufficient absorption of vitamins and nutrients.
In advance, you should start taking vitamin B9 and multivitamins for pregnant women. It is advisable to diversify your diet by saturating it with all the necessary nutrients. With late pregnancy, you need to undergo regular medical examinations and be more attentive to your new condition.
Down syndrome (or disease)- chromosomal pathology, causing impaired mental development and accompanied by characteristic changes in appearance. Normally, a person has 46 chromosomes (23 from the mother and 23 from the father). In Down syndrome, another extra chromosome is passed from either parent. Chromosomes are structures within cells that contain DNA. An additional chromosome is the cause of impaired growth and development of the child. Down's disease is the most common trisomy (in 1959, researchers found an "extra" third chromosome) - trisomy on a very small 21st chromosome. This is the most common form of chromosomal anomaly in the European part of Russia: its frequency is 1 in 600-800 newborns (about 8000 children with Down's disease are born in the Russian Federation every year).Down's disease occurs with the same frequency among both boys and girls. There is a clear relationship between the age of the mother and the frequency of this anomaly: the older the mother, the greater the risk of having a child with Down's disease, since with age, the egg accumulates more and more genetic errors. Until the age of 35, this risk is relatively low, but then it increases significantly. This risk is 16 times higher in pregnancy at 40-46 years than at 20-24 years. Father's age plays a much smaller role.
The disease is clearly diagnosed from the first days of life, but to confirm it, a blood test is carried out in order to identify an additional chromosome. Symptoms in infancy and later age are manifested by a combination of a number of developmental anomalies. Children are more often of short stature, are distinguished by dementia (90% are imbecile) due to underdevelopment of the brain (therefore, education in special schools is not always possible).
Such children have a characteristic appearance: a small round head with a sloping back of the head, oblique eye slits, epicanthus (a vertical fold of the crescent-shaped skin covering the inner corner of the palpebral fissure (by the way, this syndrome was originally called Mongolism); normally observed in representatives of the Mongoloid race), short a nose with a wide flat bridge of the nose, small deformed ears, a half-open mouth with a protruding transversely striated tongue and a protruding lower jaw, a peculiar gait with awkward movements, tongue-tied. Their muscles are sharply hypotrophied, as a result of which the range of motion in the joints is increased. In 19% of cases with Down's disease, characteristic Brushfield spots (whitish or pearly foci on the iris of the eye) are noticeable. Skeleton anomalies are present: deformation of the sternum, shortening and expansion of the hands and feet, the little finger is curved inward, its middle phalanx is hypoplastic. In the first year of life, such children noticeably lag behind in psychomotor development. They later begin to sit and walk. For example, they cannot sit without support for up to 2.5 years, do not walk until 4 years, begin to speak after 3 years, do not control physiological bowel movements until 7 years.
Alexander:“We were just tortured with the phrase“ Well, you understand ... ”But I told them: even if you frighten us now that the child has begun to grow wings, claws, a beak and that he is a dragon in general, it means there will be a dragon. Leave us alone, we will give birth to a dragon and we will be happy. So write in all your documents: "They will be happy and glad of the dragon" - and forget about us.
We, I say, are completely in the hands of the Lord God - so it is up to him to decide what our child will be like. By the way, we were almost right about the dragon, because Semyon has two fused fingers on his left leg, like a dragon's. So what? Evelina and I have worked out a formula for ourselves: love without conditions. And then everyone talks about love, but silently means some "if". If healthy, if handsome, if rich, if smart ... "
After months of waiting, the boy Semyon appeared very weak, the first 7 days of his life he had a hard time because of problems with his heart. Health workers again suggested that the spouses give up and abandon the baby, to which the offended parents responded negatively. They decided to fight at all costs and ... to rejoice! After discharge, the baby was provided with the most important thing - mother's milk, fresh air and the love of parents. Evelina says that the couple stayed in shock and stupor for only 3 days, and then serious work began. Of course, not everything went smoothly, and nerves were giving up, and tears were shedding ... The Downside Up organization rendered great help, where they drew information and strength to act. Doctors warned: so that Senya's health did not deteriorate, it was necessary to live without diseases for the first year. The love and care of the parents helped the boy to fulfill the prescriptions of the doctors.
Alexander:“On the night when Semyon was born, a girl was born next to him, absolutely healthy, so cool! .. Our Semyon is such a rag that is already in intensive care… And a girl is born. We do not just refuse, we take Seeds to ourselves, but they refuse the girl that night! After such things, I want to try to do something with this society ... "
Now Semyon is 2.5 years old, he is not much different from other children, he goes to kindergarten, develops and brings a lot of joy to his beloved mom and dad. Parents created pages for their little son on social networks, which are regularly updated with fresh photos of the boy's successes. By this, Evelina and Alexander want to warn all parents expecting "sunny children" from fatal mistakes. Alexander plans to open a charitable foundation that will prepare parents for the appearance of babies with Down syndrome. 
Many will say that parents with the means have the opportunity to raise such children. And what about the rest? The following "non-stellar" example from the AIF magazine will tell for us.
Nastya and Lesha.
She was 19 years old, he was 23. A beautiful young couple. Happy pregnancy. Excellent results for all analyzes and examinations. The long-awaited birth of a daughter. And silence.
“All the doctors suddenly fell silent. I saw that they were bent over her and did not understand what was happening, ”Nastya recalls. Later, the pediatrician told Nastya that the newborn girl was suspected of Down syndrome. A blood test is required to confirm.
“But don't worry,” the doctor added cheerfully. - After all, there are also defective toys - they can be taken back to the store. The world swayed and shrank to the size of a microscopic particle called a chromosome. 46 or 47 chromosomes? All life now depended on it.
Nastya waited a week for the test results. Each of these days will remain in her memory forever. Children were brought to other mothers for feeding, but she did not: “Why do you need? You will get used to it! .. ". Wherever she went: for procedures, in the corridor, she heard: “Refuse urgently, this is a freak. Have you seen her diagnoses ?! Young - you will give birth to others. And then the husband will leave, and all friends will turn away, you will be left alone, and even with such a burden. " Barely recovering from childbirth, unable to meet with her family, she approached the children's room, peering into the tiny face. Doctors told her: "Look, everything is written on her face!" And Nastya saw a small child - with pink cheeks, huge blue eyes and blond hair, standing like a "mohawk" on the top of her head ...
She already knew that it was - Dasha... After all, this is the name they gave her even when she was in the stomach. Daughter Dasha is the most beloved, the happiest ...
Photo: From the personal archive of Anastasia
There was a discharge department under the window of Nastya's ward. And every day she saw through the window how joyful mothers with children in their arms came out, how their relatives welcomed them ... Nastya could communicate with her family only by video phone. As shocked and confused as she was, they did not know what to say. Everyone was waiting for the results of the analysis. Meanwhile, the doctors, it turns out, took turns personally meeting each of them: with her husband, mother, mother-in-law. And, like Nastya, they told them terrible predictions: “This is not a child, but a vegetable in the garden: it will never go, will not speak, and will not recognize any of you. And in general, he will die in your arms. Bring it home and dies. " A week later, confirmation came - Dasha had Down syndrome. On the same day, without consulting Nastya, the family removed all children's things from the house - a stroller, a crib, the first tiny clothes ... And a little later, under the incessant pressure of doctors and in the presence of a lawyer, Nastya and Lesha wrote a rejection of the child. Each separately, because they never had the opportunity to meet and talk with the whole family. The woman lawyer was very lively and cheerful: “Well, we found something to grieve about! Young, healthy, give birth to a dozen more and forget everything, like a bad dream. " Dasha's parents met only when Nastya left the door of that very discharge department. One.
Photo: From the personal archive of Anastasia
They told friends and acquaintances that the child had died. And we tried to live as before. “We managed to pretend to others, even to each other. But in front of myself ... I was then ready to go to any job, to do anything - just not to think ... ". Nastya remembers her first visit to the child's home even now. They drove along with Lyosha - and from the street they heard children crying. For some reason, it immediately became clear that it was Dasha. She lay in the infectious disease box and cried - her leg was stuck between the bed slats. She could not get it out, and there was no one to help - there was not enough staff for everyone ... Then it was easier to come, they got used to it. It was more difficult to leave. “She lay and looked at us. And we had to turn away from this look and leave ... ".
Love syndrome
Once Nastya realized that next time she simply would not be able to leave like this - without Dasha. The doctors said they could take the child home for the weekend. Then Nastya took a vacation and took her daughter for a whole month. “When we were dressing her, the nanny decided that we, as usual, dress for a walk. And when she suddenly realized that we were taking to stay home, she suddenly burst into tears: "Lord, even if you, Dasha, never came back here!" The nanny did not know that her words would be prophetic. However, then no one knew this. And Lyosha was categorically against taking the child, even temporarily. To visit, to help somehow - yes, but not to take on such a responsibility. They even agreed that they would live separately this month: Nastya and Dasha with her mother, and Lyosha with hers.
Photo: From the personal archive of Anastasia
All month Nastya waited for other predictions of doctors to come true: when friends and family would start turning away, when they would point fingers at her daughter. But everything was different: the whole family immediately fell in love with Dasha, and her husband came every weekend and fiddled with her. On the street now it was no longer Nastya who looked longingly into other people's carriages, but looked at her into the carriage with the words: “Oh, what a miracle! So glorious! " During this month, one-year-old Dasha, who, upon arriving home, could only lie down, learned to sit down and walk by the arms by herself, has changed a lot ... And meanwhile the month was coming to an end. "Can you get her back?" - Mom asked Nastya once. Of course, Nastya could not. But Lyosha could not change his mind either. She tried to persuade him for a long time, giving a variety of reasons: “I just cannot give it away now. It should at least be supported, allowed to grow stronger ... ”. But then I realized that one cannot demand from a person what he cannot give. “The innate maternal instinct, which Lesha could not have, spoke in me. And I had no time for arguments and resentments: I had to raise the child. " Lyosha and Nastya are officially divorced. Later, Lesha will remember this - the rejection of Dasha and the divorce - as the biggest mistake in his life. However, he still continued to visit Nastya and her daughter and help them.
Photo: From the personal archive of Anastasia
Dasha grew and developed. Nastya has already got used to the fact that even doctors, seeing her, are amazed: “And this is a child with Down's syndrome ?! And we didn’t know that such a thing was possible, we were taught something completely different ... ”. But still, the first place where she heard the words: "What a wonderful child you have!" was the Center for Early Development of the Downside Up Foundation. Nastya accidentally found out about him from other parents, came with two-year-old Dasha to classes - and realized that she had begun new life... “It was there that I finally began to 'let go'. And not only me, but also Lyosha, because he also came with us. There we saw other parents, other children - both small and grown up - and we were finally convinced that it was not scary. We saw what a huge work is being done to help us - and realized that we are not alone. "
Dasha recently turned 15 years old. After finishing her studies at Downside Up at the age of seven, she studies in a regular school, on the basis of which a specialized class for children with disabilities has been created: some of the subjects they take along with everyone else, and Russian and mathematics - according to an easier program. She has a big loving family: mom, dad, grandmother, great-grandmother, beloved little sister Anya.
Photo: From the personal archive of Anastasia
At the invitation of the First Lady of Great Britain, Dasha went to London to light the lights at the Christmas tree, took part in photography for the Love Syndrome calendar, and talked to journalists and celebrities. She is very polite and caring, it is easy and pleasant to be with her. Dasha finds mutual language with everyone, but with special affection for children and the elderly, who respond in kind to her. Nastya thinks that Dasha's future profession will be related to caring for people. And nothing that while in our country people with Down syndrome have practically no employment opportunities. This is the next step and one day we will definitely take it.
After all, if until recently the only officially employed person with Down syndrome in Russia was Maria Nefedova, an assistant teacher at Downside Up, now everyone has learned the story of Nikita Panichev, who works as an assistant chef in one of the Moscow coffee houses. And recently, a case of employment of a person with Down syndrome occurred in Omsk - a young man, 20-year-old Alexander Belov, began working as a cleaner to prove that special people can also be useful to society. Well, and at the same time save money for a course of dolphin therapy and new jeans.
Photo: From the personal archive of Anastasia
And Nastya and Lyosha are still together. They began to live as a family shortly after Dasha went to classes at Downside Up. And after a while they got married again. This time - by getting married in a church. Parents who have faced the same situation and do not know what to do are still coming to their house and calling them. Nastya and Lyosha firmly made it a rule not to convince or persuade anyone of anything. They only tell their story: only facts, without hiding anything. Of course, more than once Nastya was asked the question: "Have you ever regretted your decision to take the child?" You can probably ask it only without seeing them all together: Nastya, Lyosha, Dasha, Anya ...
Down syndrome is a type of genetic disorder that inhibits physical growth as well as the development of intellectual abilities.
A physician from England, John Langdon Down, first described this pathology in 1866. He took a special interest in people with intellectual disabilities. Although he was the first to isolate some of the distinguishing characteristics of people with this anomaly, it was not until 1959 that Dr. Jerome Lejeune, who was studying chromosomes, discovered the cause of the syndrome, an extra chromosome 21.
Why are babies born with Down syndrome?
All cells of the human body contain a nucleus, where the genetic material is stored in the genes. Genes carry the codes for all of our inherited traits and are grouped along rod-like structures called chromosomes. Typically, there are 46 chromosomes in the nucleus of each cell, arranged in 23 pairs. One chromosome from a pair is passed on from the father, and the other from the mother.
Down syndrome is a genetic disease in which people have 47 chromosomes in their cells instead of 46. They have an extra chromosome 21.
Typically, in this disorder, a person inherits two chromosome 21 from the mother (instead of one) and one chromosome 21 from the father, so that each cell contains 3 copies of chromosome 21, not 2 (hence this genetic abnormality is also known as trisomy 21). In this disorder, an extra copy of chromosome 21 leads to an increase in the expression of genes located on it. It is believed that the activity of these additional genes leads to many of the manifestations that characterize Down syndrome.
Types of genetic changes
Three genetic variations can cause Down syndrome.
In about 92% of cases, Down syndrome is due to the presence of an extra chromosome 21 in every cell.
In such cases, an additional chromosome arises during the development of either an egg or a sperm. Therefore, when an egg and a sperm combine to form a fertilized egg, there are three, not two, chromosome 21. As the embryo develops, an extra chromosome is repeated in each cell.
Robertsonian translocation and partial trisomy 21
In some people, parts of chromosome 21 fuse with another chromosome (usually chromosome 14). This is referred to as a Robertson translocation. The person has a normal set of chromosomes, one of which contains additional genes from chromosome 21. The child inherits additional genetic material from chromosome 21 from his parent with a Robertson translocation, and he will have Downism. Robertsonian translocations occur in a small percentage of the disorder.
It is extremely rare that very small fragments of chromosome 21 are included in other chromosomes. This phenomenon is known as partial trisomy 21.
Mosaic trisomy 21
Another small percentage of cases of the syndrome is mosaic. In a mosaic form, some cells in the body have 3 copies of chromosome 21, while the rest are unaffected. For example, a person may have trisomy 21 skin cells while all other cell types are normal. Mosaic Down Syndrome can sometimes go unnoticed because a person with this genetic variation does not necessarily have all of the physical characteristics and is often less cognitively impaired than a person with complete trisomy 21. This can lead to misdiagnosis.
Regardless of the genetic variation that causes the syndrome, people with the disorder have an extra critical portion of chromosome 21 in some or all of their cells. The extra genetic material disrupts the normal course of development, causing the symptoms of trisomy 21.
Down syndrome prevalence
About 1 in 800 babies are born with trisomy 21. About 6,000 babies are born with this disorder every year.
There is no test that can be done before conception to determine if a future newborn will have the syndrome. A baby with trisomy 21 can be born to any couple, but the risk increases with the age of the pregnant woman. On the other hand, young women give birth to most children with chromosomal abnormalities. This is determined by the fact that, compared with adult women, younger women are more likely to give birth to children.
Large studies have been conducted to study the likelihood of having a child with trisomy 21, associated with the age of the mother. The following data were obtained:
- in a woman in her 20s, the risk of giving birth to a child with an anomaly is 1 in 1500;
- in a 30-year-old woman - 1 in 800;
- in a woman at 35, the probability rises to 1 in 270;
- at 40 - the probability is 1 in 100;
- a 45-year-old woman has a 1 in 50 chance or more.
The risk of conceiving a child with a chromosomal abnormality is actually greater than the figures given. This is due to the fact that approximately 3/4 of embryos or developing fetuses with a genetic disorder will never reach full development, and therefore a miscarriage will occur.
It was found that from 1989 to 2008, cases of detection of trisomy 21 in the prenatal and postnatal periods became more frequent, despite the small difference in fertility. But the number of babies born with this genetic disorder has declined slightly due to improvements and wider use of prenatal screening. It has led to an increase in the frequency of detection of the disorder during pregnancy and, as a result, its termination. Without this improved screening, since women tend to have children at an older age, it is believed that the number of live newborns with a genetic abnormality would otherwise almost double.
If a woman previously had a child with such a pathology, then the risk increases by 1% that the second baby will also suffer from this chromosomal abnormality.
Clinical manifestations
While not all people with this disorder have the same physical characteristics, there are some characteristics that commonly occur with this genetic disorder. This is why patients with trisomy 21 have a similar appearance.
Three features that are found in every individual with Down syndrome:
- epicanthosis folds (extra skin of the inner eyelid, which gives the eyes an almond shape);
- eye section according to the Mongoloid type;
- brachycephaly (head with a large transverse diameter);
Other features that people with this genetic disorder have (but not all):
- include light spots in the eyes (Brushfield spots);
- small, slightly flat nose;
- small open mouth with protruding tongue;
- low set small ears that can be folded;
- abnormally formed teeth;
- narrow palate;
- tongue with deep cracks;
- short arms and legs;
- not tall in comparison with healthy children of the same age;
- small feet with an increased gap between the thumb and second toe.
None of these physical features are abnormal in themselves, and they do not cause serious problems or cause any pathology. However, if the doctor sees these manifestations together, he is likely to suspect that the child has Down syndrome.
Common pathologies in Down syndrome
In addition to the features appearance there is an increased risk of a number of medical problems:
Hypotension
Nearly all affected infants have weak muscle tone (hypotension), which means that their muscles are weakened and appear somewhat flexible. With this pathology, it will be difficult for a child to learn to roll, sit, stand and speak. In newborns, hypotension can also cause feeding problems.
Hypotension results in delayed motor development in many children and may develop orthopedic problems. It cannot be cured, but physical therapy can help improve muscle tone.
Visual impairment
Vision problems are common with the syndrome and are likely to increase with age. Examples of such visual disorders are myopia, hyperopia, strabismus, nystagmus (involuntary eye movements with high frequency).
In children with trisomy 21, an eye exam should be done as early as possible because the above problems can be corrected.
Heart defects
About 50 percent of babies are born with heart abnormalities.
Some of these heart defects are mild and can be corrected on their own without medical intervention. Other heart abnormalities are more severe and require surgery or medication.
Loss of hearing
Hearing problems with Down syndrome are not uncommon. Otitis media affects about 50 to 70 percent of children and is a common cause of hearing loss. Deafness, present at birth, affects about 15 percent of children with this genetic disorder.
Gastrointestinal disorders
About 5 percent of sick babies will have gastrointestinal problems, such as a narrowing or blockage of the intestines or a blocked anus. Most of these pathologies can be corrected with surgery.
Lack of nerves in the large intestine (Hirschsprung's disease) is more common in individuals with the syndrome than in the general population, but is still quite rare. There is also a strong association between and trisomy 21, which means it is more common in people with this disorder than in healthy individuals.
Endocrine abnormalities
With Down syndrome, hypothyroidism (insufficient production of thyroid hormones) often develops. It can be congenital or acquired, secondary to Hashimoto's thyroiditis (an autoimmune disease).
Hashimoto's thyroiditis, which causes hypothyroidism, is the most common thyroid disease in affected patients. The disease usually begins at school age. Rarely, Hashimoto's thyroiditis results in hyperthyroidism (overproduction of hormones).
Individuals with the syndrome have an increased risk of developing type I.
Leukemia
Very rarely, in about 1 percent of cases, an individual may develop leukemia. Leukemia is a type of cancer that affects the blood cells in the bone marrow. Symptoms of leukemia include easy bruising, fatigue, pale complexion, and unexplained fevers. Although leukemia is a very serious disease, the survival rate is high. It is usually treated with chemotherapy, radiation, or bone marrow transplants.
Intellectual problems
All individuals with the syndrome have some degree of mental disability. Children tend to learn more slowly and have difficulty with complex reasoning and judgment. It is impossible to predict what level of mental retardation those born with a genetic disorder will have, although this will become clearer with age.
The IQ range for normal intelligence is 70 to 130. A person is believed to have a mild intellectual disability when his IQ is 55 to 70. The moderately mentally retarded person has an IQ of 40 to 55. Most affected people have an IQ IQ ranges from mild to moderate intellectual disability.
Despite their IQ, people with the syndrome can learn and develop throughout their lives. This potential can be maximized through early intervention, quality education, rewards, and high expectations.
Features of behavior and psychiatric status
In general, natural spontaneity, true kindness, cheerfulness, gentleness, patience and tolerance are characteristic. Some patients show anxiety and stubbornness.
Most affected children do not have any associated psychiatric or behavioral disorders. Up to 38% of children can have mental health problems associated with them. These include:
- attention deficit hyperactivity disorder;
- oppositional defiant disorder;
- autism spectrum disorder;
- obsessive compulsive disorder;
- depression.
Down syndrome is usually suspected after a baby is born due to a set of unique characteristics. However, a karyotype test (chromosome study) is performed to confirm the diagnosis. This test involves taking a blood sample from a child to look at the chromosomes in the cells. Karyotyping is important to determine the risk of recurrence. Down syndrome translocation requires karyotyping of parents and other relatives for correct genetic counseling.
There are tests that doctors can do before the baby is born:
Screening tests
Screening tests determine the likelihood of a fetus having Down syndrome or other diseases, but they do not definitively diagnose a genetic disorder.
The different types of research include:
- blood tests, which are used to measure protein and hormone levels in a pregnant woman. Abnormally increased or decreased levels may indicate a genetic disorder;
- ultrasound can identify congenital heart defects and other structural changes, such as additional skin at the base of the neck, which may indicate the presence of the syndrome.
A combination of blood test and ultrasound results are used to assess the likelihood that the fetus has Down syndrome.
If there is a high probability on these screening tests, or if there is a higher chance due to maternal age, newer non-invasive tests may report very high (> 99%) or very low (<1%) вероятности, что у плода есть синдром Дауна. Однако эти тесты не являются диагностическими.
Diagnostic tests
When screening tests have shown a high likelihood of the fetus having a genetic disorder, additional diagnostic tests are done. They can determine if a fetus has Down syndrome with almost 100 percent accuracy. However, because these tests require the use of a needle to obtain a sample from inside the uterus, they carry a slight increased risk of miscarriage and other complications.
The different types of diagnostic testing include:
- Chorionic villus sampling, in which a small sample of the placenta is taken for specific genetic testing. Chorionic biopsy is used to detect any condition that is associated with certain chromosomal abnormalities. This test is usually performed during the first trimester between 10-14 weeks of pregnancy.
- Amniocentesis, a prenatal diagnostic method in which a needle is inserted into the amniotic sac that surrounds the baby. Amniocentesis is most commonly used to detect Down syndrome and other chromosomal abnormalities. This test is usually performed in the second trimester after 15 weeks.
Since this is a chromosomal abnormality, there is no cure for Down syndrome. Therefore, treatment for the condition focuses on controlling symptoms, intellectual problems, and any medical conditions that people experience throughout their lives.
Treatment may include:
- using medications to treat common disorders such as hypothyroidism;
- surgery to correct a heart defect or blockage of the intestine;
- selection of glasses and / or hearing aids, as poor eyesight and hearing loss are possible.
Most children need physical therapy to tone up muscle tone, as the hypotension present will inhibit the development of motor skills. And early intervention, starting from infancy, is critical to children reaching their full intellectual potential so that they can become as independent as possible when they reach adulthood.
Surgery
Surgery for heart defects
Certain birth defects are found in children with the syndrome. One of these is an atrioventricular septal defect, in which a hole in the heart interferes with normal blood flow. This defect is eliminated by surgery, namely by correcting the hole and, if necessary, restoring any valves in the heart that may not close completely.
People born with this defect need to be monitored by a cardiologist throughout their lives.
Surgery for gastrointestinal diseases
Some babies are born with a deformity of the duodenum called duodenal atresia. The defect requires surgery to repair, but is not considered an emergency if there are other more urgent medical problems.
Early intervention system
The sooner children with Down syndrome receive the personalized care and attention they need to address specific health and developmental problems, the more likely they are to reach their full potential.
An early intervention system is a program of therapy, exercise, and interventions to address developmental delays that children with Down syndrome or other disorders may experience.
A variety of treatments can be used in lifelong early intervention programs to promote the highest possible development, independence and productivity. Some of these treatments are listed below.
Physical therapy includes activities and exercises that help build motor skills, build muscle strength, and improve posture and balance.
Physical therapy is especially important in early childhood because physical ability is at the core of other skills. The ability to roll over, crawl and stand up helps infants learn about the world around them and how to interact with it.
The physical therapist will also help the child compensate for physical problems such as low muscle tone so that long-term problems are avoided. For example, a physical therapist can help a child create an effective walking pattern, rather than one that causes leg pain.
Speech therapy can help children with Down syndrome improve their communication skills and use language more effectively.
Children with trisomy often learn to speak later than their peers. A speech therapist will help them develop early communication skills such as sound imitation.
In many cases, affected children understand the language and want to communicate before they can speak. The speech therapist will show your child how to use alternative means of communication until he learns to speak.
Learning to communicate is an ongoing process, so a person with the syndrome may also benefit from speech and language therapy in school and later in life. The specialist should help develop the skills of conversation, pronunciation, reading comprehension, as well as facilitate the study and memorization of words.
Preparation for work involves learning how to find ways to adapt everyday tasks and conditions in accordance with the needs and abilities of a person.
This type of therapy teaches self-care skills such as eating, dressing, writing, and using the computer.
The professional may suggest special tools to help improve day-to-day functioning, such as a pencil that is easier to grip.
At the high school level, a specialist helps adolescents identify a profession or occupation that matches their interests and strengths.
Immunization
Proper immunization is extremely important because structural abnormalities make children with the syndrome more susceptible to infections of the upper respiratory tract, ear, nose, and throat. All affected children should receive the standard recommended series of vaccines: DPT, vaccines against polio, Haemophilus influenzae, and mumps.
The hepatitis B vaccine series must start at birth.
Annual influenza vaccination has been suggested as another means of reducing the incidence.
Features of feeding babies
A baby with Down syndrome can be breastfed. are generally easier to digest than mixtures of all types. In addition, affected children who are breastfed suffer less from diseases of the respiratory system, as well as a lower incidence of otitis media, respiratory allergies. also contributes to the motor development of the oral cavity, which is the basis of speech.
Sucking problems associated with hypotension or heart defects can make breastfeeding difficult, especially in premature babies. In this situation, you can bottle feed the baby with expressed milk. Often after a few weeks, the baby's ability to suck often improves.
If the infant does not gain sufficient body weight while breastfeeding, the formula should be partially added.
Many babies with Down syndrome tend to be "sleepy babies" in their first weeks. Therefore, feeding only on demand can be ineffective both in terms of calories and in meeting the child's vitamin and nutrient needs. In this situation, the infant should be awakened to feed at least every three or two hours if only breastfeeding is used.
When formula feeding, you should also wake your baby at least every three hours to ensure adequate calorie and nutrient intake.
If weight gain is not a problem, or an infant with Down syndrome has a particular medical disorder at this time, no specific formula is recommended.
The infant's diet should be expanded according to the usual schedule. Delayed administration, however, may delay the administration of solid foods. Parents should remember that it takes a lot of patience to teach a child to spoon and drink from a cup.
Conclusion
In recent decades, people with this chromosomal abnormality have noticeably increased life expectancy. Back in 1960, a child with a genetic disorder often did not live to be ten. Now the estimated life expectancy for such people reaches 50-60 years.
Down syndrome cannot be cured, but even with this condition, your child can still be happy as long as you provide the necessary love, care and treatment.
- chromosomal anomaly, in which the karyotype contains additional copies of genetic material on the 21st chromosome, that is, trisomy on chromosome 21 is observed. on the neck, shortening of the limbs, short-fingered, transverse palmar fold, etc. Down syndrome in a child can be detected prenatally (according to ultrasound, chorionic villus sampling, amniocentesis, cordocentesis) or after birth on the basis of external signs and genetic research. Children with Down syndrome need correction of concomitant developmental disorders.
ICD-10
Q90
General information
Down's syndrome is an autosomal syndrome in which the karyotype is represented by 47 chromosomes due to an additional copy of the 21st chromosome pair. Down syndrome is recorded with a frequency of 1 in 500-800 newborns. The sex ratio among children with Down syndrome is 1: 1. Down syndrome was first described by English pediatrician L. Down in 1866, but the chromosomal nature and essence of the pathology (trisomy on chromosome 21) was revealed almost a century later. The clinical symptoms of Down syndrome are diverse: from congenital malformations and mental abnormalities to secondary immunodeficiency... Children with Down syndrome require additional medical care from various specialists, and therefore they are a special category in pediatrics.
Down syndrome causes
Normally, the cells of the human body contain 23 pairs of chromosomes (normal female karyotype 46, XX; male - 46, XY). In this case, one of the chromosomes of each pair is inherited from the mother, and the other from the father. The genetic mechanisms for the development of Down syndrome lie in a quantitative disorder of autosomes, when additional genetic material is attached to the 21st pair of chromosomes. The presence of trisomy on chromosome 21 determines the traits characteristic of Down's syndrome.
The appearance of an additional chromosome may be due to a genetic accident (non-divergence of paired chromosomes in ovogenesis or spermatogenesis), a violation of cell division after fertilization, or inheritance of a genetic mutation from the mother or father. Taking into account these mechanisms, three variants of karyotype anomaly in Down syndrome are distinguished in genetics: regular (simple) trisomy, mosaicism, and unbalanced translocation.
Most cases of Down syndrome (about 94%) are associated with simple trisomy (karyotype 47, XX, 21+ or 47, XY, 21+). In this case, three copies of the 21st chromosome are present in all cells due to a violation of the separation of paired chromosomes during meiosis in the maternal or paternal germ cells.
About 1-2% of cases of Down syndrome are in the mosaic form, which is caused by a violation of mitosis in only one cell of the embryo at the blastula or gastrula stage. In mosaicism, trisomy of the 21st chromosome is detected only in the derivatives of this cell, and the rest of the cells have a normal chromosome set.
The translocation form of Down syndrome occurs in 4-5% of patients. In this case, the 21st chromosome or its fragment is attached (translocated) to any of the autosomes and, during meiosis, leaves with it into the newly formed cell. The most frequent "objects" of translocation are chromosomes 14 and 15, less often - on 13, 22, 4 and 5. Such a rearrangement of chromosomes can be random or inherited from one of the parents, which is a carrier of a balanced translocation and has a normal phenotype. If the carrier of the translocation is the father, then the probability of having a child with Down syndrome is 3%, if the carrier is associated with the maternal genetic material, the risk increases to 10-15%.
Risk factors for having children with Down syndrome
The birth of a child with Down syndrome is not related to the lifestyle, ethnicity and region of residence of the parents. The only reliably established factor that increases the risk of having a baby with Down syndrome is the age of the mother. So, if in women under 25 years of age the probability of having a sick child is 1: 1400, by 35 years already 1: 400, by 40 years - 1: 100; and by 45 - 1:35. First of all, this is due to a decrease in control over the process of cell division and an increase in the risk of chromosome nondisjunction. However, since the birth rate in young women is generally higher, then, according to statistics, 80% of children with Down syndrome are born to mothers under the age of 35. According to some reports, the age of the father over 42-45 years also increases the risk of developing Down syndrome in the child.
It is known that in the presence of Down syndrome in one of the identical twins, this pathology in 100% of cases will be present in the other. Meanwhile, in fraternal twins, as well as siblings, the likelihood of such a coincidence is negligible. Other risk factors include the presence of persons with Down syndrome in the family, the mother's age under 18, the carriage of a translocation by one of the spouses, closely related marriages, random events that disrupt the normal development of the germ cells or the embryo.
Thanks to preimplantation diagnostics, conception with the help of ART (incl. in vitro fertilization) significantly reduces the risk of having a child with Down syndrome in parents from risk groups, but does not completely exclude this possibility.
Down syndrome symptoms
Carrying a fetus with Down syndrome is associated with an increased risk of miscarriage: spontaneous abortion occurs in about 30% of women at 6-8 weeks. In other cases, children with Down syndrome are usually born full-term, but have moderate hypoplasia (body weight 8-10% below average). Despite various cytogenetic variants of chromosomal abnormalities, most children with Down syndrome have typical external signs that suggest the presence of pathology already at the first examination of the newborn. neonatologist... Children with Down syndrome may display some or all of the physical characteristics described below.
80-90% of children with Down syndrome have craniofacial dysmorphies: flattened face and bridge of the nose, brachycephaly, short wide neck, flat nape, deformation of the auricles; newborns - a characteristic fold of skin on the neck. The face is distinguished by a Mongoloid cut of the eyes, the presence of an epicanthus (a vertical fold of skin covering the inner corner of the eye), microgenia, a half-open mouth, often with thick lips and a large protruding tongue (macroglossia). Muscle tone in children with Down syndrome is usually decreased; there is hypermobility of the joints (including atlanto-axial instability), chest deformity (keeled or funnel-shaped).
The characteristic physical signs of Down syndrome are meek limbs, brachydactyly(brachymesophalangia), curvature of the little finger (clinodactyly), transverse ("monkey") fold in the palm, wide distance between 1 and 2 toes (sandal fissure), etc. When examining children with Down syndrome, white spots are revealed along the edge of the iris (Brushfield spots ), gothic (arched palate), malocclusion, grooved tongue.
With the translocation variant of Down's syndrome, external signs are more pronounced than with simple trisomy. The severity of the phenotype in mosaicism is determined by the proportion of trisomic cells in the karyotype.
Children with Down syndrome are more likely than others in the population to have UPU (patent ductus arteriosus , DMZHP , DMPP , Fallot's tetrad and etc.), strabismus , cataract , glaucoma , hearing loss , epilepsy , leukemia, gastrointestinal defects ( esophageal atresia, duodenal stenosis and atresia, Hirschsprung's disease), congenital hip dislocation... Typical dermatological problems of puberty are dry skin , eczema , acne , folliculitis.
Children with Down syndrome are classified as often ill; they are harder to tolerate childhood infections, more often suffer pneumonia , otitis media , ARVI , adenoids , tonsillitis... Weak immunity and congenital defects are the most likely cause of death of children in the first 5 years of life.
Most patients with Down syndrome have intellectual disabilities - usually mild to moderate mental retardation. The motor development of children with Down syndrome lags behind their peers; there is a systemic speech underdevelopment.
Down syndrome patients are prone to developing obesity, constipation, hypothyroidism , alopecia areata , testicular cancer, early onset of Alzheimer's disease, etc. Men with Down syndrome, as a rule, sterile; fertility of women is markedly reduced due to anovulatory cycles... The height of adult patients is usually 20 cm below average. Life expectancy is about 50-60 years.
Down syndrome diagnostics
For the prenatal detection of Down syndrome in the fetus, a prenatal diagnostic system has been proposed. Screening of the first trimester is carried out at 11-13 weeks of pregnancy and includes the identification of specific ultrasound signs of an anomaly and the determination of the level of biochemical markers (hCG, PAPP-A) in the blood of a pregnant woman. Between 15 and 22 weeks of gestation, a second trimester screening is performed: obstetric ultrasound, maternal blood test for alpha-fetoprotein, hCG and estriol. Taking into account the woman's age, the risk of having a child with Down syndrome is calculated (accuracy - 56-70%; false-positive results - 5%).
Pregnant women at risk of having a baby with Down syndrome are offered prenatal invasive diagnosis : chorionic biopsy , amniocentesis or cordocentesis with karyotyping fetus and medical geneticist consultation. Upon receipt of data for the presence of Down syndrome in a child, the decision of the issue of prolongation or termination of pregnancy remains with the parents.
Newborns with Down syndrome in the first days of life need to be accompanied by a speech therapist and an oligophrenopedagogue by a cardiologist.
The education of children with Down syndrome, as a rule, is carried out in a special correctional school, however, within the framework of integrated education, such children can also attend a regular mass school. In all cases, children with Down syndrome are classified as children with special educational needs, therefore, they need additional help from teachers and social educators, the use of special educational programs, and the creation of a favorable and safe environment. An important role is played by psychological and pedagogical support of families where "sunny children" are brought up.
Down syndrome prognosis and prevention
The learning and socialization opportunities of individuals with Down syndrome vary; they largely depend on the intellectual abilities of children and on the efforts of parents and educators. In most cases, children with Down syndrome are able to instill the minimum household and communication skills necessary in everyday life. At the same time, there are cases of success of such patients in the field of fine arts, acting, sports, as well as obtaining higher education. Adults with Down syndrome can lead an independent life, master simple professions, and create families.
Prevention of Down syndrome can only be discussed from the standpoint of reducing possible risks, since the likelihood of having a sick child exists in any couple. Obstetricians-gynecologists advise women not to postpone pregnancy to a later age. Family genetic counseling and a prenatal screening system are intended to help predict the birth of a child with Down syndrome.
