What is klinefelter syndrome?

Klinefelter Syndrome

Klinefelter syndrome

Klinefelter syndrome is a genetic condition that affects males. Typically, males have one X and one Y chromosome; males with Klinefelter syndrome have at least two X chromosomes in addition to their Y chromosome and, in rare cases, as many as three or four.

Symptoms, when present, vary from one person to another depending on the number of extra X chromosomes and how many cells in the body are affected. Symptoms may include a lack of fully developed secondary male sexual characteristics—such as the growth of the testicles and penis, deeper voice, and body hair—by adulthood. These men usually have infertility. Other symptoms may include delayed speech development, poor verbal skills, intellectual disability, or emotional and behavioral problems. Males with more than one extra X chromosome generally have more severe symptoms.

Klinefelter syndrome usually goes undiagnosed until the preteen years (around ages 11 to 12), when males often begin puberty. In some males, Klinefelter syndrome is never diagnosed and does not cause problems.

The main treatment for Klinefelter syndrome is hormone therapy to increase testosterone. Other treatments vary depending on the symptoms and may include educational support for language and learning difficulties and counseling or social skills training for behavior problems.

What are the symptoms of Klinefelter syndrome?

Many men who have Klinefelter syndrome do not have obvious symptoms. Others have sparse body hair, enlarged breasts, and wide hips. In almost all men the testicles remain small. In some men the penis does not reach adult size. Their voices may not be as deep. They usually have infertility. But they can have a normal sex life.

Some boys with Klinefelter syndrome have language and learning problems.

How is Klinefelter syndrome treated?

Males with Klinefelter syndrome can be given testosterone, a hormone needed for sexual development. If treatment is started around the age of puberty, it can help boys with the sexual development of their bodies.

Testosterone is given by injection or through a skin patch or gel. The treatment usually continues throughout a man's life but does not help infertility.

Speech therapy and educational support can help boys who have language or learning problems.

How is Klinefelter syndrome diagnosed?

Klinefelter syndrome usually is not diagnosed until the time of puberty. At this point, the boy's testicles fail to grow, and you may start to notice other symptoms.

To find out if your son has Klinefelter syndrome, your doctor will ask questions about his past health, do a physical exam, and order tests, such as a hormone test and chromosome analysis.

In adult men, other tests may be done, such as semen analysis.

Sometimes Klinefelter syndrome is found before a baby is born (prenatally). Genetic tests on cells collected from amniocentesis or chorionic villus sampling (CVS) can show when a baby boy has Klinefelter syndrome. So the condition may be found when a pregnant woman has genetic tests for another reason.

How can you care for your child who has Klinefelter syndrome?

Be actively involved in your child's care. Learn about the treatments and how you can provide support at home. Encourage your child to be active and independent. If counseling is needed, look for someone who has worked with children who have this condition.

What causes Klinefelter syndrome?

The presence of an extra X chromosome in males most often occurs when the genetic material in the egg splits unevenly. But it can also occur when the genetic material in the sperm splits unevenly. Even though Klinefelter syndrome is a genetic condition, it is not passed down through families. So, parents who have a child with Klinefelter syndrome are not any more likely than other couples to have another child with the condition.

What is Klinefelter syndrome?

Klinefelter syndrome is a genetic condition that affects males. Klinefelter syndrome occurs when a boy is born with one or more extra X chromosomes. Most males have one Y and one X chromosome. Having extra X chromosomes can cause a male to have a variety of physical traits.

Many men with an extra X chromosome are not aware that they have it, and they lead normal lives. Klinefelter syndrome occurs in about 1 out of 1,000 males.

How can you help your son who has Klinefelter syndrome?

If your son has been diagnosed with Klinefelter syndrome:

  • Recognize your feelings. It is natural for parents to feel that they have done something to cause Klinefelter syndrome. But this condition is beyond anyone's control. Allow yourself time to deal with your feelings, and talk with your son's doctor about your concerns.
  • Educate yourself about the condition. The common problem for parents is fear of the unknown. Educating yourself will help you learn how to help your son.
  • Support your son. Provide education appropriate for his age about Klinefelter syndrome and give him the emotional support and encouragement he needs. Remind him that most men who have Klinefelter syndrome go through life with few problems.
  • Be actively involved in your son's care. Talk with your doctor about his treatment. If counseling for behavioral problems is needed, or if your son has difficulty reading or has poor verbal skills, get help from qualified professionals who have experience working with boys who have Klinefelter syndrome.
  • Encourage your son to take part in activities to improve his physical motor skills, such as karate, soccer, basketball, baseball, or swimming.
  • Work with your son's teachers, principal, and school administrators.
    • Contact his teachers on a regular basis to compare how he is doing at home and at school.
    • When appropriate, let your son be present for talks with his teachers. Use brief notes, telephone calls, and meetings to identify and solve problems.
    • Provide articles and pamphlets to your son's teachers and school principal about Klinefelter syndrome.
  • Encourage your son's independence. Although it is important to be supportive, realize that watching over your son too much can send the message that you think he is not able to do things on his own.

©2011-2024 Healthwise, Incorporated

The content above contains general health information provided by Healthwise, Incorporated, and reviewed by its medical experts. This content should not replace the advice of your healthcare provider. Not all treatments or services described are offered as services by us. For recommended treatments, please consult your healthcare provider.