by Greg Richards (background by Bridget, age 9)
Ninety-five percent of people with Down syndrome (trisomy 21) have 47 chromosomes per cell (they have an extra #21 chromosome). This common type of trisomy 21 is called non-disjunction.
Three to four percent of people with Down syndrome have Robertsonian Translocation, where the number of chromosomes is normal, but the extra chromosome 21 material is attached with chromosome 14.
The remainder have a rare type of Down syndrome in which some of their cells have 46 chromosomes and some have 47 chromosomes. This is called mosaicism.
If you would like an in-depth description of the history and genetics of Down syndrome, see Dr. Len Leshin's essay from his excellent internet resource on Down syndrome, www.ds-health.com.
with Down syndrome do not have the same genetic makeup as other children,
they are more like typical children than they are different.
In the USA, we prefer to use the term "Child with Down syndrome" instead of "Down's Child", "Down syndrome child", "Down's kid", or just "Down's". Here's the philosophy behind it:
It would be nice
if everyone could think of children with Down syndrome as children first,
and their disability second, hence "Child with Down syndrome".
|Disclaimer:||The author is not a medical professional, and information here is not to be substituted for medical advice. Please contact your child's physician if you have medical questions.|
Revised: August 28, 2001