Down Syndromealso known as trisomy 21, is a genetic disorder caused by the part of third copy of chromosome21. It is commonly associated with growth delay, characteristic facial features and mild to moderate intellectual disability. Globally, as of 2010, Down syndrome occurs in about 1 per 1000 births and results in about 17,000 deaths. About 1.4 per 1000 live births in the United States. At age 20, the chance is one in 1441; at age 30, it is one in 959; at age 40, it is one in 84; and at age 50 it is one in 44.
There are no medical treatments for intellectual disability associated with Down syndrome, but improved medical care has greatly enhanced quality of life and increased life expectancy. It may include genetic counseling, standard immunizations and well child care.