Chromosomes contain the genetic makeup of your body. They occur in 23 pairs within the body. Down syndrome is a problem with chromosome pair 21. There is extra genetic material on the chromosome that may be caused by:
An extra chromosome—This type is called Trisomy 21. This results from an error in cell division in the egg or sperm.
Extra chromosomes in some cells—This type is called Mosaic Trisomy 21.
Part of the chromosome breaking off and reattaching to another chromosome—This type is called translocation trisomy. In about one third of individuals, the translocation is inherited from a parent.
Infants born with Down syndrome may have some or all of the following physical features:
Flat facial features, a somewhat depressed nasal bridge and a small nose
Upward slanted eyes, small skin folds on the inner corner of the eyes
Short neck with loose skin
Misshaped and/or low set ears
White spots on the colored part of the eye
Single skin crease in the palm of the hand
Excess flexibility in joints
Sight and hearing problems
Large and protruding tongue
Excessive space between the large and second toe
The degree of medical problems and intellectual disability is different for each person. Talents, abilities, and pace of development will be different, too. People with Down syndrome may be born with or develop:
Doctors can usually identify a child born with Down syndrome at birth. When Down syndrome is suspected, a blood test will be done to confirm it.
Down syndrome may also be diagnosed before birth. There are screening tests and diagnostic tests to help identify chormosome abnormalities before birth.
A screening test is done to estimate the risk of having a child with Down syndrome. Your doctor will use the results of a variety of blood tests and the mother's age to estimate the risk. Blood tests may include:
Triple screen—Alpha-fetoprotein Plus
Cell-Free Fetal DNA Testing
Screening may be done as early as 11 weeks. It may also include both
and blood screening. There should be a follow-up in the second trimester for those who have a negative screening.
A small amount of women who have screening will be given false-positive readings. This means the test indicates Down syndrome even when it does not exist.
Diagnostic tests will tell if the fetus actually has Down syndrome. These tests include:
Chorionic villus sampling (CVS)—Usually done between 10 and 12 weeks
Some newborns may need surgery to repair serious medical problems, like heart defects.
Treatment may be needed for severe problems or to help with developmental delays. Living at home and receiving special therapy helps children with Down syndrome achieve their full potential. Most people with the condition can actively participate in the community. This includes activities at schools, jobs, and various leisure activities. Some people with Down syndrome live with family, some live with friends, and some live independently.
Infants with Down syndrome may take longer to feed. A child with Down syndrome will also start talking, playing, and performing other activities later than normal.
Learning opportunities may be increased with:
School programs designed to meet the child's special needs.
Mainstreaming children into regular public school classes with additional support as needed
Benn P, et al. Prenatal detection of Down syndrome using massively parallel sequencing (MPS): A rapid response statement from a committee on behalf of the Board of the International Society for Prenatal Diagnosis, 24 October 2011.
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Down Syndrome. National Institute of Child Health and Human Development website. Available at: ...(Click grey area to select URL) Updated April 3, 2013. Accessed May 21, 2013.
Malone FD, Canick JA, et al. First- and second-trimester evaluation of risk (FASTER) research consortium.
First-trimester or second-trimester screening, or both, for Down's syndrome.
N Engl J Med. 2005;353:2001-2011.
What is Down syndrome? National Down Syndrome Society website. Available at: ...(Click grey area to select URL) Accessed May 21, 2013.