Down Syndrome was first described by British doctor Langdon Down in 1866.However,it was not until 1959 that French geneticist Jerome Lejeune first reported that individuals with Down Syndrome almost always possess an extra chromosome in which pair?

Question

Quizplus · Accepted Answer

Jerome Lejeune discovered that Down Syndrome is caused by an extra copy of chromosome 21, making it also known as trisomy 21.

Down Syndrome Was First Described by British Doctor Langdon Down