What are the causes of Down Syndrome?

The causes of Down syndrome, a genetic disorder occurring in approximately one of each 800 birth, were traced to an aberrant cell division. There are three different types of irregular cell division, which are known to be among the causes of Down syndrome. Each of the three types of abnormalities is associated with the present other genetic material on the chromosome number 21. If scientists know, Chromosome 21 is exclusively responsible for the development of Down syndrome.

trisomy 21, one of the three genetic abnormalities known to be the causes of Down syndrome is associated with more than 90 percent of cases. A child born with a genetic disorder of Trisome 21 has three copies of a chromosome 21 instead of two in all cells in his body. This type of downy syndrome is caused by irregular cell division during the development of egg or semen before fertilization; Somehow eggs or sperm do not divide correctly. Almost in all cases the lower system caused by a trisomy 21 disorder, another chromosome comes from the mother's egg andnot the father's sperm.

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Mosaic Down syndrome is a rare form of this syndrome, which represents only 1-2 percent of cases. Some of the child cells - but not all - have another copy of chromosome 21. This is the type of mosaic of abnormal and normal cells in the body, where some cells have normal chromosomes 46, but others have 47.

Down translocation syndrome is a final genetic aberration known to be one of the causes of Down syndrome. This is the only form of Down syndrome that can be handed over from parent to child. This genetic disorder can only be added to about 4 percent of Down syndrome cases, and only half of them are the result of inheritance. In the Translapage of Ation, one of the parents has some genetic material that has been disordered, but there is no other chromosome in any cell. The parent does not have the downsIn the syndrome, but may pass the damaged genetic material to the child that could develop the syndrome. A mother with damaged genetic material has about 12 % risk of handover and the father has about 3 % chance.