Down syndrome is a genetic disorder caused when abnormal cell division results in an extra full or partial copy of chromosome 21. This extra genetic material causes the developmental changes and physical features of Down syndrome.

Which parent gives Down syndrome?

Heres what the algorithm doesnt account for: Extra genetic material can also attach itself to chromosome 21 in the sperm. Scientists agree that Down syndrome can be attributed to the father in 5 to 10 percent of cases, and some believe that number may be as high as 20 percent.

Does the mother or father cause Down syndrome?

There is no definitive scientific research that indicates that Down syndrome is caused by environmental factors or the parents activities before or during pregnancy. The additional partial or full copy of the 21st chromosome which causes Down syndrome can originate from either the father or the mother.

How does Down syndrome get inherited?

Most cases of Down syndrome are not inherited. When the condition is caused by trisomy 21, the chromosomal abnormality occurs as a random event during the formation of reproductive cells in a parent. The abnormality usually occurs in egg cells, but it occasionally occurs in sperm cells.