Down Syndrome Defined
What is Down syndrome?
Down syndrome is a genetic condition that occurs in approximately one in every 733 live births in the United States. It affects people of all ages, races and economic levels and is the most frequently occurring chromosomal abnormality. The majority of people with Down syndrome have a third copy of chromosome 21 in all their cells, instead of the usual two. This results in the person with Down syndrome having 47 chromosomes in each cell instead of the usual 46. This additional genetic material alters the course of development and causes the characteristics associated with the syndrome. Down syndrome affects over 350,000 people in the United States alone. Recent advances in our understanding of Down syndrome have resulted in dramatic improvements in the life span and potential of those who are affected. Today, our challenge is three-fold: to increase understanding of Down syndrome and the true potential of those who have it; to advocate for full inclusion for people with Down syndrome; and to fund scientific research into the cause and treatment of Down syndrome.
Chromosomes
Chromosomes are thread like structures, which are in every cell of the body. Each cell has 46 chromosomes arranged in 23 pairs; each pair of chromosomes carries genetic information. Down syndrome affects the 21st chromosome by the presence of three chromosomes instead of two. The scientific name of Down syndrome is Trisomy 21. The extra copy of the 21st chromosome is what causes the characteristics of Down syndrome. These characteristics very in each individual with Down syndrome, they are present in visual characteristics, developmental delays and different health issues. For more information on all of these please refer to our different links listed below.
Chromosomes in a Typical Male
(In Females, the last pair of chromosomes would be two "X's" instead of "X" and"Y")
Chromosomes in a Male with Down Syndrome
Click on image to enlarge
image credit: U.S. Department of Energy Human Genome Program, http://www.ornl.gov/hgmis.
Resources
Please note that the Down Syndrome Family Support and Advocacy Group is not endorsing any person or product listed below. This is nothing more than a list of resources, and it is up to each individual to decide what is appropriate for their situation. If you have any questions, please contact the manufacturer, service provider, or you can ask questions on one of the Down syndrome listservs.
National Down syndrome Association
National Down Syndrome Congress
Down Syndrome Information on the Internet
Health Issues by Dr. Len Leshin
Using Karyotypes to Detect Genetic Disorders
Benefits for Children with Disabilities
Michiana Down syndrome Listserv
Indiana Family 2 Family Network
Foundation for Music and Healing, Inc.