![]() |
||||||||||||
|
||||||||||||
Down Syndrome Report
Down Syndrome Report Down Syndrome Report by: SCHOOL SUX The chromosomal abnormality involved in most cases of Down syndrome is trisomy-21, or the presence of three copies of the 21st chromosome. As a result, the affected person has 47 chromosomes in all body cells instead of the normal 46, although how this causes the condition's symptoms is not yet known. Scientists assume that the reason for the abnormal chromosomal assortment is the fertilization of an ovum having 24 chromosomes by a sperm with a normal assortment of 23, but they have also found that the sperm can carry the extra chromosome as well. The abnormal ovum or sperm is derived from a germ cell in which the pair of 21st chromosomes holds together and passes into the same sperm or ovum instead of separating. In the type of Down syndrome called translocation, the extra chromosome 21 material is attached to one of the other chromosomes; when some, but not all, of the body's cells carry an extra chromosome 21, the condition is a type of Down syndrome called mosaicism. Because of the extra chromosome 21, children with Down syndrome often have some characteristic physical features, such as a small head, a flat face, slightly upward slanted eyelids, skin folds at the inner corners of the eyes, small nose and mouth, and small hands and feet. Most of these characteristic do not interfere with the child's functioning, a doctor primar... This is ONLY a preview of the article. If you would like to view the entire document, you must subscribe to Academic Library. Please register below now!
|
|
Home | Register | Login | FAQ | Forgot Password | Privacy Policy | Disclaimer | Close Account | Contact Us | Logout Copyright 1998-2007 Academic Library. Academic Library is designed only to assist students and researchers in the preparation of their own work. Anybody who use our services are responsible not only for writing their own papers, but also for citing Academic Library as a source when doing so. By accessing and using this page you agree to the Disclaimer. If you wish to cancel your subscription to Academic Library, please click here. |
||