Causes of Down Syndrome

You did not do anything to cause your child to have Down syndrome. Down syndrome may affect anyone. The risk of having a child with Down syndrome increases as a women's age increases. Your child's Down syndrome may have happened through any of the following:

A normal sex cell with one chromosome 21 is joined by an abnormal sex cell with two chromosome 21's.
A piece of chromosome 21 breaks off and joins another chromosome pair.
A problem occurred after fertilization where a normal cell divides and ends up with more chromosomes than normal.
Its also Down children have a particular pattern of symptoms leading to their mental retardation. Their total brain volume is generally smaller than average for their age. Measurements show a shorter diameter in the anterior-posterior section of the brain as well. The brains of Down children have other characteristic differences in shape, including a precipitous slant to the posterior sections of the brain and an underdeveloped superior temporal gyrus.

Down syndrome is the most common genetic source of mental retardation, occurring in one out of every eight hundred births. The syndrome is not associated with a particular race and is not limited to certain socioeconomic group. The chances of having a baby with Down syndrome do increase with the mother's age.