What is Down syndrome? Down syndrome is a genetic disorder that includes a combination of birth defects including some degree of mental retardation, characteristic facial features and, often, heart defects, visual and hearing impairment and other health problems. There are approximately 350,000 individuals with Down syndrome according to the National Down Syndrome Society. What causes Down syndrome? Down syndrome is usually caused by an error in cell division called non-disjunction. Normally a fertilized egg possesses only …showed first 75 words of 377 total…

…showed last 75 words of 377 total…and some may marry. Women with Down syndrome are fertile and can have children. The life expectancy among adults with Down syndrome is about 55 years, though life span varies between different people. When was Down syndrome discovered? Down Syndrome was discovered in 1959 by the French physician, Jerome Lejeune. He identified Down syndrome as a chromosomal anomaly. Instead of the usual 46 chromosomes present in each cell, Lejeune observed 47 in the cells of individuals with Down syndrome.