Down syndrome or Down's syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is usually associated with physical growth delays, mild to moderate intellectual disability, and characteristic facial features. The average IQof a young adult with Down syndrome is 50, equivalent to the mental ability of an eight- or nine-year-old child, but this can va…
Down syndrome | Genetic and Rare Diseases Information ...
Jun 11, 2012 · Intellectual and Developmental Symptoms. Cognitive impairment, problems with thinking and learning, is common in people with Down syndrome and usually ranges from mild to moderate. Only rarely is Down syndrome associated with severe cognitive impairment. 1.
Generally, the chance of having a Down syndrome birth is related to the mother's age. Under age 25, the odds of having a child with Down syndrome are about 1 in 1,400. At age 35, the odds are about 1 in 350.
People with Down syndrome have distinct physical features which may include slanted eyes, a short neck, a flat-looking face and nose, abnormal outer ears, a small chin but large tongue, and a single crease on the palm. People who have Down syndrome also tend to have poor muscle tone and stunted growth.
What are the risk factors of Getting Down syndrome?
In general, the two most significant factors that increase the risk of Down syndrome include the age of the mother, and a family history of the condition. This may mean that a parent or family member is simply a carrier of Down syndrome, but does not actually have the condition, or that a family member or sibling was born with it.
Down syndrome is by far the most common and best known chromosomal disorder in humans and the most common cause of intellectual disability. It is primarily caused by trisomy of chromosome 21 (see the image below), which gives rise to multiple systemic complications as part of the syndrome.