How is down syndrome inherited?
Down syndrome is not really inherited but more of a random event. We have 23 pairs of chromosomes in our cells (for a total of 46). Down syndrome is also called trisomy 21, which means you have 3 chromosomes at the number 21, instead of the normal two. This results when the chromosomes fail to split when the cell divides, therefore you will get two number 21 chromosomes from one parent, and the normal one 21 chromosome from the other. I think there are some predisposing genes that cause the failure of the 21 chromosome to split, but not much is known about them.
In most cases it is not inherited. But here is a great site for oodles and oodles of info. http://ghr.nlm.nih.gov/condition=downsyn…
