• Down syndrome - Mayo Clinic

      www.mayoclinic.org/diseases-conditions/down-syndrome/basics/.../con-20020948 Down syndrome — Comprehensive overview covers causes, risk factors and diagnosis of this genetic disorder.
    • What Is Down Syndrome? - National Down Syndrome Society

      www.ndss.org/Down-Syndrome/What-Is-Down-Syndrome National Down Syndrome Society 666 Broadway, 8th Floor New York New York 10012 800-221-4602 info@ndss.org
    • Down syndrome - Genetics Home Reference

      ghr.nlm.nih.gov/condition/down-syndrome Down syndrome is a chromosomal condition that is associated with intellectual disability, a characteristic facial appearance, and weak muscle tone ...
    • Down syndrome - Wikipedia, the free encyclopedia

      en.wikipedia.org/wiki/Down_syndrome Down syndrome (DS or DNS) 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. [1]
    • What Is Down Syndrome? -- Types and Causes

      www.webmd.com/children/guide/understanding-down-syndrome-basics Down syndrome is one of the most common genetic birth defects. Usually, children born with the condition have some degree of mental retardation, as well as ...
    • Down Syndrome | Features | CDC

      www.cdc.gov/features/down-syndrome/index.html Learn more about Down syndrome and about Keaton, a boy with Down syndrome. Each year, about 6,000 babies born in the United States have Down syndrome. 1 Down syndrome ...
    • Down Syndrome - Symptoms, Diagnosis, Treatment of Down ...

      www.nytimes.com/health/guides/disease/down-syndrome/overview.html Down syndrome is a genetic condition in which a person has 47 chromosomes instead of the usual 46.