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Thursday, August 23, 2007

Causes of Down Syndrome

Down syndrome cause by an errors of genetic condition, its can occur during cell division. Human cells normally have 46 chromosomes which can be arranged in 23 pairs during cell division, Sometimes this division does not happen properly and one cell may contain 22 chromosomes and the other may contain 24 chromosomes (this accident is called "nondisjunction").

Children or infant those diagnosed as down syndrome are have an extra (third) copy of the 21st chromosome (Trisomy 21). If the cell containing 24 chromosomes combines with a cell containing 23 chromosomes, the new cell will contain 47 chromosomes instead of 46.

Because of that, during cell division in down syndrome cases may one cell has two 21st chromosomes instead of one, so the resulting fertilized egg has three 21st chromosomes (called trisomy 21). Other conditions arise if the duplicated chromosome is a different chromosome. If the trisomy is chromosome 13, the person will have Patau's syndrome. If the trisomy is chromosome 18, the person will have Edward's syndrome.

The parents who has a child with Down syndrome due to translocation trisomy 21, its possible for them an increased likelihood of Down syndrome in future pregnancies, because one of the two parents may be a balanced carrier of the translocation.

Down syndrome is not attributable to any behavioral activity of the parents or environmental factors, it is happened cause by genetic's problem only. No one knows why this condition can be happened and there's no way to prevent the chromosomal error that causes down syndrome.

1 Comments:

Anonymous newshealthtoday said...

Common cases of Down syndrome are outcome from trisomy 21, which is each cell in the body;possess three copies of chromosome 21 instead of the usual two copies.

October 4, 2013 at 12:07 PM  

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