Klinefelter syndrome, also known as XXY syndrome, is a condition in boys and men that’s caused by an extra X chromosome. It can affect physical and mental development.

Klinefelter syndrome is the most commonly occurring sex-chromosome disorder, and it often goes undiagnosed. In this article the authors discuss the diagnosis and the clinical features and ...

Klinefelter's syndrome, named after Harry F. Klinefelter, who first described the syndrome in 1942, [1,2] is the most frequent major abnormality of sexual differentiation in men with two or more ...

In addition to 'Klinefelter's syndrome', there may be other similar symptoms or signs that better match your side effect. These have also been listed below for your convenience.

Why Klinefelter's Syndrome Causes Infertility Men with Klinefelter's syndrome have an extra X chromosome, meaning their genetic makeup is “47, XXY” instead of the usual “46, XY.” ...

Klinefelter syndrome is a genetic condition that occurs when a male is born with an extra copy of the X chromosome, affecting an estimated 1 in 1,000 individuals. Symptoms of Klinefelter syndrome may ...

Klinefelter Syndrome. The symptoms and characteristics of Klinefelter syndrome vary widely among males with the disorder. Many boys with the syndrome show few or only mild signs.