Klinefelter Syndrome

Klinefelter Syndrome
Klinefelter Syndrome

Overview Of Klinefelter Syndrome

Klinefelter syndrome is a genetic condition that occurs in males when they have an extra X chromosome.

Commonly Associated With

47 X-X-Y syndrome; XXY syndrome; XXY trisomy; 47,XXY/46,XY; Mosaic syndrome; Poly-X Klinefelter syndrome

Causes Of Klinefelter Syndrome

Most people have 46 chromosomes. Chromosomes contain all of your genes and DNA, the building blocks of the body. The 2 sex chromosomes (X and Y) determine if you become a boy or a girl. Girls normally have 2 X chromosomes. Boys normally have 1 X and 1 Y chromosomes.

This syndrome results when a boy is born with at least 1 extra X chromosome. This is written as XXY.

Klinefelter syndrome occurs in about 1 out of 500 to 1,000 baby boys. Women who get pregnant after age 35 are slightly more likely to have a boy with this syndrome than younger women.

Symptoms Of Klinefelter Syndrome

Infertility is the most common symptom of this syndrome.

Symptoms may include any of the following:

  • Abnormal body proportions (long legs, short trunk, shoulder equal to hip size)
  • Abnormally large breasts (gynecomastia)
  • Infertility
  • Sexual problems
  • Less than normal amount of pubic, armpit, and facial hair
  • Small, firm testicles
  • Tall height
  • Small penis size

Exams & Tests

Klinefelter syndrome may first be diagnosed when a man comes to the health care provider because of infertility. The following tests may be performed:

  • Karyotyping (checks the chromosomes)
  • Semen count

Blood tests will be done to check hormone levels including:

Treatment Of Klinefelter Syndrome

Testosterone therapy may be prescribed. This can help:

  • Grow body hair
  • Improve the appearance of muscles
  • Improve concentration
  • Improve mood and self-esteem
  • Increase energy and sex drive
  • Increase strength

Most men with this syndrome are not able to get a woman pregnant. But, an infertility specialist may be able to help. Seeing a doctor called an endocrinologist may also be helpful.