What causes trisomy 21?
trisome 21 results when a child has three cells in all its cells than a typical two copies of chromosome 21. This type of abnormal cell division occurs during egg or sperm development. Trisomy 21 is by far the most common cause of downy syndrome because it occurs in more than 90 percent of cases. This condition is not hereditary or there are no known environmental or behavioral causes. Since 2011 there is no treatment.
The normal human cell contains 23 pairs of chromosomes or fiber springs deoxyribonucleic acid (DNA), which carry genes in the linear order. Each pair consists of one chromosome from the mother of the person and the other of the father, a total of 46 chromosomes. Trisomy occurs when there are three copies of chromosome rather than a normal two. Therefore, a person born with three rather than two copies of chromosome 21 in each cell has a trisomy of 21.Chromosomes or 23 pairs before the cell division subjugates. During this division, 46 chromosomes are divided in half, so eggs and sperm eachThe surface with 23 chromosomes or one copy of each pair. When the sperm cell of the fertilization cell fertilizer, 23 chromosomes in each combination create a complete set of 46 chromosomes or 23 new pairs.
trisomy 21 may occur when eggs or sperm cell with 46 chromosomes that are divided in half, keep three copies of chromosome 21 in each cell if this egg or semen is fertilized instead of one copy of the chromosome 21: two of the abnormal cell and one of the normal cell. This special copy of the chromosome 21 causes Down syndrome.
Since trisomy 21 is caused by abnormal cell division, it is not considered a hereditary state. The source of this chromosomal mistake is not understood, but no scientific study Suggest that one of the parents can do something to cause or prevent it. There is no known medicine for genetic condition but programs of early interventions specific to theThose with Down syndrome can help with the development of cognitive, sensory and motor skills.
Chromosomal abnormality, such as Trisome 21, can be detected, while the child is in the uterus by analyzing amniotic fluid or placenta cells. Amniocentesis, sampling of chorionic lips and percutaneous umbilical blood sampling are all diagnostic tests that can be performed during pregnancy to diagnose the syndrome. These types of analysis are generally much more accurate than fetal ultrasound, but may pose a risk of abortion.
Chromosome 21 is the smallest human chromosome and is believed to contain approximately 300 to 400 genes. In addition to Down syndrome, genes are related to Chromosome 21 with other diseases, including Alzheimer's disease, Romano-Ward syndrome and non-syndromic deafness. Some cancers, such as Acute lympoblastic leukemia, were associated with the translocation of genetic material between other chromosomes and chromosome 21.