Hotmail
Messenger
My MSN
MSN Directory
|
Picture | |
from | Encarta |  |
Down Syndrome |
||||||
 |
||||||
|
||||||
| Down syndrome is often called Trisomy 21 because most people with this condition have three copies of the number 21 chromosome—one of the smallest of the human autosomes. In this karyotype, the sex chromosomes—marked with letters instead of numbers—are XX rather than XY, showing that these chromosomes belong to a female. Down syndrome almost always results in mental retardation, though the severity of the retardation varies. | ||||||
|
||||||
| Science Source/Photo Researchers, Inc. | ||||||
|
||||||
|
||||||
| Appears in these articles: | ||||||
|
||||||
| Mental Retardation; Down Syndrome | ||||||
|
||||||
|
||||||
|
Advertisement
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||
© 2008 Microsoft
  |