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Diseases

Genetic and Rare Diseases Information Center (GARD)

Klinefelter syndrome


Other Names for this Disease
  • Klinefelter's syndrome
  • XXY syndrome
Related Diseases
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.

Your Question

My husband has Klinefelter syndrome. I have read a lot of things about this syndrome, but I want to know more about the future. He is 33-years-old, and he didn't take any medication for Klinefelter syndrome in the past. What is the chance of him becoming a father?

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

What is Klinefelter syndrome?

Klinefelter syndrome (KS) is a condition that occurs in males when they have an extra X chromosome. Some males with KS have no obvious signs or symptoms while others may have varying degrees of cognitive, social, behavioral, and learning difficulties. Adults with Klinefelter syndrome may also experience primary hypogonadism (decreased testosterone production), small testes, enlarged breast tissue (gynecomastia), tall stature, and/or infertility. KS is not inherited, but usually occurs as a random event during the formation of reproductive cells (eggs and sperm). Treatment is based on the signs and symptoms present in each person.[1][2][3]
Last updated: 10/13/2015

What are the signs and symptoms of Klinefelter syndrome?

The signs and symptoms of Klinefelter syndrome (KS) vary among affected people. Some men with KS have no symptoms of the condition or are only mildy affected. In these cases, they may not even know that they are affected by KS. When present, symptoms may include:[2][3][1]
  • Small, firm testicles
  • Delayed or incomplete puberty
  • Breast growth (gynecomastia)
  • Reduced facial and body hair
  • Infertility
  • Tall height
  • Abnormal body proportions (long legs, short trunk, shoulder equal to hip size)
  • Learning disablity
  • Speech delay

Whether or not a male with KS has visible symptoms depends on many factors, including how much testosterone his body makes, if he is mosaic (with both XY and XXY cells), and his age when the condition is diagnosed and treated.[1]
Last updated: 10/12/2015

Is Klinefelter syndrome inherited?

Klinefelter syndrome is not inherited, but usually occurs as a random event during the formation of reproductive cells (eggs and sperm). An error in cell division called nondisjunction can result in reproductive cells with an abnormal number of chromosomes. For example, an egg or sperm cell may gain one or more extra copies of the X chromosome as a result of nondisjunction. If one of these reproductive cells contributes to the genetic makeup of a child, the child will have one or several extra X chromosomes in each of the body's cells.[2]
Last updated: 10/12/2015

How might Klinefelter syndrome be treated?

Because symptoms of Klinefelter syndrome (KS) can sometimes be very mild, many people are never diagnosed or treated. When a diagnosis is made, treatment is based on the signs and symptoms present in each person. This may include:[1][3][4]
  • Educational interventions - As children, many people with Klinefelter syndrome qualify for special services to help them in school. Teachers can also help by using certain methods in the classroom, such as breaking bigger tasks into small steps.
  • Therapeutic options - A variety of therapists, such as physical, speech, occupational, behavioral, mental health, and family therapists can often help reduce or eliminate some of the symptoms of Klinefelter syndrome such as poor muscle tone; speech and language problems; or low self-confidence.
  • Medical management - About half of people with KS have low testosterone levels, which may be raised by taking supplemental testosterone. Having a more normal testosterone level can help affected people develop bigger muscles, a deeper voice, and facial and body hair. Many healthcare providers recommend testosterone therapy when a boy reaches puberty. However, not all males with KS benefit from testosterone therapy. Some affected people may opt to have breast removal or reduction surgery.

The Eunice Kennedy Shriver National Institute of Child Health and Human Development's Web site offers more specific information on the treatment and management of Klinefelter syndrome. Please click on the link to access this resource.
Last updated: 10/13/2015

Are people with Klinefelter syndrome able to have children?

The vast majority of people with Klinefelter syndrome (KS) are azoospermic (have no sperm present in the ejaculate). However, motile sperms in the ejaculate and even spontaneous pregnancies resulting from fathers with KS have been described, although such cases are rare. In general, people with mosaic KS (those that also have a 46,XY cell line) are less severely affected so the chance of finding sperm in the ejaculate is significantly higher than in non-mosaic cases. In the past, the use of donor semen or adoption were the only possible ways of having a child. However, in recent years, testicular sperm extraction (TESE) followed by intracytoplasmic sperm injection (ICSI) have helped more than 100 people with KS became biological parents.[5]

People with KS should not automatically assume they are infertile without thorough testing.[1]
Last updated: 10/13/2015

References
Other Names for this Disease
  • Klinefelter's syndrome
  • XXY syndrome
Related Diseases
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.