Klinefelter Syndrome
Klinefelter syndrome is the presence of an extra X chromosome in a male.
Causes, incidence, and risk factors
Humans have 46 chromosomes. Chromosomes contain all of your genes and DNA, the building blocks of the body. Two of these chromosomes, the sex chromosomes, determine if you become a boy or a girl. Females normally have two of the same sex chromosomes, written as XX. Males normally have an X and a Y chromosome (written as XY). Klinefelter syndrome results in males who have at least one extra X chromosome. Usually, this occurs as a result of one extra X (written as XXY). Klinefelter syndrome is found in about 1 out of every 500-1,000 newborn males. Women who have pregnancies after age 35 are slightly more likely to have a boy with this syndrome than younger women.
Symptoms
The most common symptom is infertility. Other symptoms may include:
- Small, firm testicles
- Small penis
- Only a little bit of pubic, armpit, and facial hair
- Sexual problems
- Enlarged breasts ( gynecomastia)
- Tall height
- Abnormal body proportions (long legs, short trunk)
Testosterone therapy may be prescribed. This can help:
- Increase strength
- Improve appearance of muscles
- Grow body hair
- Improve mood and self esteem
- Increase energy and sex drive
- Improve concentration
Credit: National Institute of Health.