<unk>  is a condition caused by a chromosome aneuploidy. Affected males have an extra X chromosome. The principal effects are the development of small testicles and reduced fertility. A variety of other physical, behavioral differences, and problems are common. The severity varies and many boys and men with the condition have few detectable symptoms. Because of the extra chromosome, individuals with the condition are usually referred to as "XXY Males", or "47,<unk>  Males".
In humans, 47,XXY is the most common sex chromosome aneuploidy in males and the second most common condition caused by the presence of extra chromosomes. Other mammals also have the<unk><unk> , including mice.
Klinefelter's syndrome
Angelman syndrome
Wolman disease
Grahmann's syndrome
Kallmann syndrome
Turner syndrome
Kostmann syndrome
Gitelman syndrome