Klinefelters Syndrome

By Victoria Meddaugh


  • In 1942, Dr. Harry Klinefelter and his coworkers at the Massachusetts General Hospital in Boston published a report about 9 men who had enlarged breasts, sparse facial and body hair, small testes, and an inability to produce sperm.
  • By the late 1950s, researchers discovered that men with Klinefelter Syndrome, as this group of symptoms came to be called, had an extra sex chromosome, resulting in a chromosomal arrangement of XXY; the usual male arrangement is XY.
  • In the early 1970s, researchers around the world sought to identify males having the extra chromosome by screening large numbers of newborn babies. One of the largest of these studies checked the chromosomes of more than 40,000 infants.
  • Based on these studies, the XXY chromosome arrangement appears to be one of the most common genetic abnormalities known, occurring as frequently as 1 in 500 to 1 in 1,000 male births.
  • While many men have an extra X chromosome, not a lot actually have Klinefelter syndrome symptoms. Many men live out their lives without ever suspecting that they have an additional chromosome.


  • Klinefelter syndrome may first be diagnosed when a man comes to the doctor because of infertility. Infertility is the most common symptom.
  • The following tests may be performed:
  • Karyotyping
  • Semen count
  • Blood tests will be done to check hormone levels including:
  • Estradiol, a type of estrogen
  • Follicle stimulating hormone
  • Luteinizing hormone
  • Testosterone

What is it?

Klinefelter's syndrome (KS) is a condition that occurs in men who have an extra X chromosome. The syndrome can affect different stages of physical, language, and social development.

The most common symptom is infertility. Boys may be taller than other boys their age, with more fat around the belly. After puberty, KS boys may have

  • Smaller testes and penis
  • Breast growth
  • Less facial and body hair
  • Reduced muscle tone
  • Narrower shoulders and wider hips
  • Weaker bones
  • Decreased sexual interest
  • Lower energy



Testosterone therapy may be prescribed.

  • Grow body hair
  • Improve 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. However, an infertility specialist may be able to help. A special doctor called an endocrinologist may also be helpful.

Big image

Works Cited