Klinefelter Syndrome

Klinefelter syndrome is the most common disorder of sex chromosomes in humans. In the early 1940s, endocrinologist Harry Klinefelter observed a tall and lean young man in a clinic setting who had small testes and enlarged breasts. Klinefelter began keeping track of these symptoms, and over the course of a year he found eight other men with the same body type, though only some of these men had enlarged breasts. He assumed these physical traits were the result of an endocrine disorder. In 1942, he published a paper describing what came to be known as Klinefelter syndrome. It was not until 1959 that Dr. Patricia Jacobs and her colleagues were able to link these traits to extra X chromosomes. Most males have one Y chromosome ...