File:Trisomy 21 newborn.jpg

Trisomy 21 (Down Syndrome) Newborn

Down syndrome or trisomy 21 is caused by nondisjunction of chromosome 21 in a parent who is chromosomally normal and is one of the most common chromosomal abnormalities in liveborn children.

The frequency of trisomy 21 in the population is approximately 1 in 650 to 1,000 live births, in Australia between 1991-97 there were 2,358 Trisomy 21 (Down) infants.

• The normal human karyotypes contain 22 pairs of autosomal chromosomes and one pair of sex chromosomes.
• The karyotype is the characteristic chromosome complement as identified by staining and can only be identified during cell division when chromosomes are folded.
• The chromosomes when organised as an image in sequence are called a karyogram or idiogram.

Links: Trisomy 21

Image Source

CDC Dr. Godfrey P. Oakley http://phil.cdc.gov/phil_images/20021209/4/PHIL_2634_lores.jpg

Description: This photograph depicts a newborn with the genetic disorder Down Syndrome, due to the presence of an extra 21st chromosome. The estimated incidence of Down Syndrome is between 1:1,000 to 1:1,100 live births. Each year approximately 3,000 to 5,000 children are born with this chromosomal disorder.

High Resolution: Right click here and select "Save Target As..." for hi-resolution image (18.89 MB)

Content Providers(s): CDC/ Dr. Godfrey P. Oakley

Creation Date: 1974

Works created by employees of the United States Government as part of their employment are considered a "Work of the United States Government." Copyright protection is not available for these works in the United States. The United States Government may receive and hold copyrights transferred to it by assignment, bequest, or otherwise.