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Down Syndrome

Down Syndrome Overview

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The earliest known depiction of a person with Down syndrome is an angel in a Flemish painting dated 1515. In 1866, Doctor John Langdon Down first described Down syndrome as a disorder, but he misunderstood how Down syndrome arises. The cause of Down syndrome was discovered rather recently in 1959.

Down syndrome is a genetic disorder and the most common cause of cognitive impairment. All individuals with Down syndrome have mild to moderate learning disabilities, distinctive facial features, and low muscle tone (hypotonia) in early infancy. Down syndrome is also often associated with heart defects, leukemia, and early-onset Alzheimer's disease. The degree to which an individual is affected by these characteristics varies from mild to severe.

In the United States, about one baby in 800 live births has Down syndrome and approximately 6000 children with Down syndrome are born in this country each year. Due to recent advances in medical care and social inclusion, life expectancy has increased dramatically for individuals with Down syndrome. About 85% of infants with Down syndrome survive 1 year, and 50% of people with Down syndrome live longer than 50 years. The average life span is greater than 55 years.

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Down Syndrome »

In 1866, Down described clinical characteristics of the syndrome that now bears his name.

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