Klinefelter syndrome

Klinefelter syndrome, 47, XXY, or XXY syndrome is a genetic disorder where people have an extra number of X chromosomes.^[1] People who have Klinefelter's Syndrome are often called "XXY Males", or "47, XXY Males".^[2]

Effects

Males who have this condition are almost always infertile. This means that they cannot father babies.^[3]

In other organisms

Any male mammal can have Klinefelter's Syndrome. The mouse is one example.^[4] Tortoiseshell or calico markings on male cats are an indicator of Klinefelter's syndrome. These cats are considered to be the model organism for Klinefelter syndrome, because the gene for a cat's orange/black coat markings is found on the X chromosome. ^[5]