The condition was first described by Dr John Langdon Down in 1862.The genetic cause of Down syndrome was discovered in 1959. In 1959 Jérôme Lejeune reported the discovery that Down syndrome resulted from an extra chromosome.World Down syndrome day:The General Assembly decided, with effect from 2012, to observe World Down Syndrome Day on 21 March each year. In order to raise public awareness of Down syndrome.World Down Syndrome Day (WDSD), 21 March, is a global awareness day which has been officially observed by the United Nations( UN)since 2012.Today the average lifespan of a person with Down syndrome is approximately 60