Klinefelter Syndrome
Klinefelter syndrome is a chromosome disorder that affects males. Normally, a male has two chromosomes that determine his sex: an X inherited from his mother and a Y inherited from his father. A male with Klinefelter syndrome has an additional X chromosome. The effects vary and may include:
- Infertility - the condition may be diagnosed when an apparently normal male is seen because they have fertility problems.
- Reduced testicle size - the testicle may not develop properly.
- Late puberty - not enough of the male hormone testosterone is produced and puberty may be late. These boys may be given testosterone treatment so they develop normal male physical characteristics like facial hair and a deeper voice.
Klinefelter syndrome occurs in around one in every 500 male babies, which makes it one of the most common abnormalities of the sex chromosomes. This condition is also known as XXY syndrome. The additional X chromosome does not influence sexual orientation.