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Klinefelter's Syndrome (XXY Condition)

Klinefelter syndrome is a condition that occurs in men as a result of an extra X chromosome. It is found in about 1 out of every 500-1,000 newborn males.

Causes

Humans have 46 chromosomes, which contain all of a person's genes and DNA. Two of these chromosomes, the sex chromosomes, determine a person's gender. Both of the sex chromosomes in females are called X chromosomes. (This is written as XX.) Males have an X and a Y chromosome (written as XY). The two sex chromosomes help a person develop fertility and the sexual characteristics of their gender.

Most often, Klinefelter syndrome is the result of one extra X (written as XXY). Occasionally, variations of the XXY chromosome count may occur, the most common being the XY/XXY mosaic. In this variation, some of the cells in the male's body have an additional X chromosome, and the rest have the normal XY chromosome count. The percentage of cells containing the extra chromosome varies from case to case. In some instances, XY/XXY mosaics may have enough normally functioning cells in the testes to allow them to father children.

Symptoms

Males who have Klinefelter syndrome may have the following symptoms: small, firm testes, a small penis, sparse pubic, armpit and facial hair, enlarged breasts (called gynecomastia), tall stature, and abnormal body proportions (long legs, short trunk).

As babies, many XXY males have weak muscles and reduced strength. As boys, between 25 percent and 85 percent of XXY males have some kind of language problem, such as learning to talk late, trouble using language to express thoughts and needs, problems reading, and trouble processing what they hear. Most XXY males are not able to father children (infertile).

Klinefelter syndrome is associated with an increased risk for breast cancer, a rare tumor called extragonadal germ cell tumor, lung disease, varicose veins and osteoporosis. Men who have Klinefelter syndrome also have an increased risk for autoimmune disorders such as lupus, rheumatoid arthritis and Sjogren's syndrome.

Treatment

The XXY chromosome pattern can not be changed. But, there are a variety of ways to treat the symptoms of the XXY condition.

  • Educational treatments – As children, many XXY males 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 the XXY condition, such as poor muscle tone, speech or language problems, or low self-confidence.
  • Medical treatments – Testosterone replacement therapy (TRT) can greatly help XXY males get their testosterone levels into normal range. Having a more normal testosterone level can help develop bigger muscles, deepen the voice, and grow facial and body hair. TRT often starts when a boy reaches puberty. Some XXY males can also benefit from fertility treatment to help them father children.

One of the most important factors for all types of treatment is starting it as early in life as possible.

 

Source

National Human Genome Research Institute, USA

National Institute of Child Health and Human Development, USA