Klinefelter syndrome (KS) occurs in some men who have more than
one X chromosome (XXY). Males usually inherit a single X
chromosome from their mother and a single Y chromosome from
their father. Males with KS get at least one extra X chromosome.
A risk factor is something that increases your chance of KS.
Women over age 35 have a slightly increased chance of having a
child with KS. There are no other known risk factors for this
disorder. XXY occurs in approximately 1 out of 580 live male
births, but many men with it do not develop KS. When KS does
develop, it usually goes undetected until puberty or sometimes
much later. Characteristics may include: - Smaller birth weight
and slower muscle and motor development For children and adults:
- Tallness with extra long arms and legs - Abnormal body
proportions (long legs, short trunk) - Enlarged breasts (common)
- Lack of facial and body hair - Small firm testes, small penis
- Lack of ability to produce sperm (common) - Diminished sex
drive, sexual dysfunction - Soc