Down’s syndrome


Down’s syndrome

Description of Down syndrome

Is the most common and best known chromosomal genetic defect in humans. It is also the best-known genetic cause of mental retardation. This syndrome is affected by about 1 newborn out of 900. Very However, depending on the age of the woman when its age, for example greater than 35 years will increase the occurrence of the defect to 1 newborn out of 400 in the case of mothers 40 years already prevalence of 1 out of 100.

Cells (except sex cells) contain 46 normal human chromosomes are two sets of 23 chromosomes.One set from the father fetus gets from other mothers because each gamete carries only 23 chromosomes. The problem with Down syndrome is the presence of 47 chromosomes, namely, the patient has three chromosome 21 instead of two (trisomy 21st pair of chromosomes). This is a cause for almost 95 percent of patients.

In a much smaller group of people who suffer from this defect is called mosaicism. This means that some cells have 47 chromosomes, and other cells of the correct ratio of 46. In these two groups of cells also depends resultant impaired person.

Another possibility is the formation of defects finding R obertsonské translocation, when the patient has 46 chromosomes, but one of them is connected to another on the 21st chromosome, creating a so-called translocated chromosome. The last very rare cause is the 23rd chromosome duplication, arises when a piece of another chromosome (partial trisomy of the 21st pair of chromosomes).

Risk factors for Down syndrome

The most important risk factor is the age of the mother. Only the occurrence of Down syndrome appears to be the optimum age for conceiving a healthy child 20-24. Later, the incidence of children with disabilities increases. Interestingly, the age of the father apparently plays no important role, surveys indicate that at least.

Another risk factor is a prospective parent who is Robertsonian translocation. This means that sex cells father or mother may have two chromosomes linked (like 2 chromosome 21). The result in the fusion of gametes then there will be three 21st chromosomes in the cells of the embryo. This risk factor may contribute to the mother but also a father.

Prevention of Down syndrome

Highlights of this defect prevention, prenatal diagnosis. This is the amount of testing before the birth, which are more common in high-risk cases where the mother is older than 35 years and so on.

The prenatal diagnosis is mainly used amniocentesis (amniocentesis), it is also possible to perform chorionic villus sampling (CVS) or take a sample of umbilical cord blood (PUBS) needle through the mother’s abdominal wall. It is also possible to investigate both parents genetically y, if not Robertsonian translocation of chromosomes, but it usually does. Such testing is in place if the parents already had a baby with Down syndrome, and therefore there is concern that any further offspring would also be threatened.

Furthermore, during pregnancy, expectant mother and her fetus undergo several routine ultrasound examination, which sometimes can reveal fetus with Down syndrome.

Signs and symptoms of Down syndrome

This defect has a lot of typical symptoms, so it manages diagnosed at birth or shortly after. Their comments, however, in different individuals vary widely. The first sign of the problem may be themuscular hypotonia newborn. It is a reduced muscle tension = reduced muscle tone. Furthermore, the patient has a small stature, short skull shape (brachycephalia) and the associated flat header.His whole face is substantially circular. The neck can be very short with loose skin at the nape, like skin abode. Furthermore earlobes built below and have an unusual shape. Eyes can be found around the edge of the iris called. Brushfieldovy spots. They are small white or yellowish spots on the edges of the iris. If the iris later turn brown stains often disappear. Patients with Down syndrome often have enlarged ridged language that they completely fit into the mouth and are therefore forced to have little mouth open. The result is a feeling that these people constantly slithering tongue. A distinctive feature is slightly askew eyes and presence epikantu. Epicanthic fold is a skin fold that runs vertically between the inner corner and bridge of the nose. Appearance very vaguely reminiscent of Asian race, so the historical name for Down syndrome is mongolism. For ethical and racial grounds, however, it is now unacceptable. Hands are typically broad with short fingers. The palms, we can find one or two grooves that run across the palm (ie. Simian crease).

Children with Down syndrome are delayed psychomotor. This means that achieve various stages of development later than healthy children. Furthermore, it is characterized by hyperactivity,restlessness manifested, vitriolic, lack of concentration, restlessness and excessive activity. Very often, their destructive behavior. Breaking objects that do not hold or will not understand them. On the other hand, some of them may act zakřiknutým impression. Despite patients’ behavior is not an obstacle in development! Much depends on parenting! An intelligence quotient (IQ index) for them is reduced to 30-60 points.

Diagnosis of Down Syndrome

The most reliable tests are genetic, which can detect any chromosomal abnormality (failure in the number or construction of chromosomes), it is done after the birth of babies, which created serious suspicion of Down syndrome, or may be made from fetal cells obtained from amniotic fluid, chorionic villus sampling and umbilical cord blood. As we have already mentioned, at-risk couples may be examined genetically and parents. Further checks carried ultrasound future mother and her child. Part of prenatal screening (ie. The triple test) is a collection of maternal blood, from which to determine the amount of certain hormones and other substances whose value is in the case of Down syndrome changed. In prenatal diagnosis with positive screening tests or because of advanced age mothers also performs amniocentesis (amniocentesis), chorionic villus sampling (CVS) or you can take a sample of cord blood (PUBS), which apply to already appointed genetic testing.

Treatment of Down Syndrome

Down syndrome is a genetic defect, so that in itself can not be cured. However, it is important to diagnose and treat the symptoms and complications of this aberration. In the case of hypotonia and psychomotor retardation is important rehabilitation and individual special education services. Thanks to the many serious complications, patients with Down syndrome live to an average of 50 years.Very course, it depends on ethnic and socio-economic conditions.

Complications of Down syndrome

Among the less severe disease include frequent upper respiratory infections and inflammation of the gums and ears. Vision is often affected by the short- or long-sightedness and šilháním (strabismus).The most serious complications include congenital heart disease (tetralogy of Fallot, cardiac septum defects etc.), and blood disease (lymphoma, leukemia) that they are up to 15 times more frequent than in the general population! Is no exception reflux of stomach acid into the esophagus, thyroid disease (hypothyroidism = thyroid hormone deficiency) and other hormonal disorders.

Other names: Down syndrome, people with mongoloid face mongolism

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