Down syndrome was first described by the English doctor John Down – this is a violation of the chromosome set, or rather the presence of an extra 21st chromosome in the chromosome set of the child received from the father or mother. An ordinary child should have 46 chromosomes, while a child with Down syndrome has 47, which leads to a violation of physical and mental retardation. This syndrome occurs in 1 in 600-700 children. For many years of research practice, scientists, finding out the causes of the violation of the divergence of the chromosomes of the egg, found that it depends on the age at which the grandmother (on the maternal side) gave birth to her daughter, on the age of the woman and man, related marriages.
Statistics
The probability of such a pathology may be in children of 20-year-old women (1:1500), and in women whose age has reached 40 years (1 in 100). For a long time, a hereditary disease was diagnosed using the method – amniocentesis, which consists in taking amniotic fluid with a thin needle through a puncture in the abdomen of a pregnant woman.
A special protein – alpha-fetoprotein (AFP), produced by the fetal liver, is released into the amniotic fluid, then enters the blood of the expectant mother, according to the level of AFP in her venous blood, and appropriate conclusions are drawn. A level below the norm indicates the development of Down syndrome in the fetus, and above the norm about the pathology of the neural tube. As time goes on, AFP levels rise steadily. However, this method cannot be used to examine all pregnant women, due to some features of each of them.
Methods of diagnosis
Only women at risk who give birth late are subjected to this procedure. There are several more diagnostic methods that allow you to recognize the development of pathology in the fetus even in the prenatal period. This is a blood test for human chorionic gonadotropin taken at a period of 10-13 weeks and an alpha-fetoprotein (ACE) study from 16 to 18 weeks. Such screening tests do not give one hundred percent guarantee in diagnosis, they can show both positive and negative results.
But a biopsy of the chorionic villi allows you to accurately verify whether the child has a chromosomal pathology or not.
The whole procedure takes place under the control of an ultrasound machine, which is used to determine the gestational age and to localize the placenta. A probe with a mirror is inserted through the vagina, a piece of chorionic villi, which are thin finger-shaped flagella, is removed. The cells of the placenta contain genetic information that allows you to determine the external structure of chromosomes and their number, as well as the sex of the child.
Signs of Down syndrome
When conducting an ultrasound of the fetus during the period of 14 weeks of pregnancy, it is possible to detect a violation of the formation of bones of the skeleton, an expansion of the collar space by more than 5 mm, echogenicity of the intestine, the presence of heart defects, an expansion of the renal pelvis, and the formation of a cyst of the choroid plexus of the brain. A highly qualified specialist can detect the absence of the nasal bone, neck folds in the fetus, indicating the accumulation of subcutaneous fluid. This all points to signs of Down syndrome.
The final diagnosis is carried out by the end of the fifth month of pregnancy. Down syndrome is recognizable, as it has features in the appearance of the child, namely: slanting eyes and a flat face, wide lips and a wide flat tongue with a longitudinal groove, a round head with a sloping forehead. Short wide neck. The auricles are set low with an adherent earlobe.
It can also be determined by the eyes, so-called Brushfield spots are observed on the iris. The hairline is sparse, the hair is soft, straight with a low growth line in the neck. Keeled or funnel-shaped chest. The upper and lower limbs are shortened, the hands and feet are extended. They are also characterized by the presence of a shortened and curved little finger with two furrows. The palms have only one transverse four-toed furrow. Changes in internal organs and abnormal growth of teeth are noted.
Conclusion
Although Down syndrome is surrounded by many prejudices and misconceptions, it makes no sense to look for the culprit. It is believed that in the future children with this pathology learn poorly, lag behind in mental development. But all this is refuted by the example of the lives of many people who have their own individual characteristics, have their own habits, hobbies. This did not stop the actor Pascal Duquenn from becoming famous and receiving the Silver Prize at the Cannes Film Festival.
Successful American actor Chris Burke lives a full life with such a diagnosis. Musician and composer Ronald Jenkins is appreciated by millions of listeners who love electronic music, he is considered a genius. There are cases when young people with Down syndrome become champions in various sports.