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It is named after John Langdon Down, the British doctor who fully described the syndrome in 1866. Some aspects of the condition were described earlier by Jean-Ãtienne Dominique Esquirol in 1838 and Ãdouard SÃ©guin in 1844. In 1957, the genetic cause of Down syndrome, an extra copy of chromosome 21, was discovered.
Navigation and exploration: 1415-1460. 1  Europe's exploration of the world begins in the 15th century, pioneered by Portugal. 2  The capture of Ceuta seems to be the event which fires Henry's enthusiasm for exploration round Africa's coasts.