Klinefelter syndrome: causes and treatment management


Klinefelter syndrome overview

Klinefelter syndrome (KS), also known as 47,XXY or XXY, is the set of symptoms that result from two or more X chromosomes in males. The primary features are infertility and small testicles. Often, symptoms may be subtle and many people do not realize they are affected.

Sometimes, symptoms are more prominent and may include weaker muscles, greater height, poor coordination, less body hair, breast growth, and less interest in sex. Often it is only at puberty that these symptoms are noticed. Intelligence is usually normal; however, reading difficulties and problems with speech are more common. Symptoms are typically more severe if three or more X chromosomes are present (48,XXXY syndrome or 49,XXXXY syndrome).

Klinefelter syndrome usually occurs randomly. An older mother may have a slightly increased risk of a child with KS. The condition is not typically inherited from one’s parents.

The underlying mechanisms involves at least one extra X chromosome in addition to a Y-chromosome such that the total chromosome number is 47 or more rather than the usual 46. KS is diagnosed by the genetic test known as a karyotype. While no cure is known, a number of treatments may help.

Physical therapy, speech and language therapy, counselling, and adjustments of teaching methods may be useful. Testosterone replacement may be used in those who have significantly lower levels. Enlarged breasts may be removed by surgery.
About half of affected males have a chance of fathering children with the help of assisted reproductive technology, but this is expensive and not risk free. Males appear to have a higher risk of breast cancer than typical, but still lower than that of females. People with the condition have a nearly normal life expectancy.

Causes of Klinefelter syndrome

You get the extra X chromosome by chance. Either the egg or sperm that came together to make you just happened to have an extra X chromosome. Older moms have a slightly higher chance of having a boy with Klinefelter, but the increase in probability is very small. You may have:
  1. An extra X chromosome in every cell, which is the most common
  2. An extra X chromosome in only some cells, called mosaic Klinefelter, where you don’t get as many symptoms
  3. More than one extra X chromosome, which is very rare and more severe

Symptoms Klinefelter syndrome

Babies: They may have problems at birth, such as a hernia or testicles that haven’t dropped into the scrotum. You may see the following other signs in babies with Klinefelter:

  • More quiet than usual
  • Slower to learn to sit up, crawl, and talk
  • Weaker muscles

Children: Boys may have low energy levels or any of the following:

  • A hard time making friends and talking about feelings
  • Problems learning to read, write, and do math
  • Shyness and low confidence
Adults: In addition to the symptoms teenagers show, men may have:

  • Infertility (can’t have children because they can’t make enough sperm)
  • Low sex drive
  • Low testosterone levels
  • Problems getting or keeping an erection

Other Conditions caused by Klinefelter syndrome

Many problems caused by Klinefelter are because of lower testosterone levels. You may have a slightly higher chance of:

Diagnosis and Tests of Klinefelter syndrome

Your doctor will start with a physical exam and questions about your symptoms and general health. He’ll likely examine your chest, penis, and testicles and do a few simple tests, such as checking your reflexes.

Your doctor may then run two main tests

Chromosome analysis: Also called karyotype analysis, this is a blood test that looks at your chromosomes.
Hormone tests: These check hormone levels in your blood or urine.

Treatment/ Management

It’s never too late to get treatment, but the earlier you start, the better.
One common treatment is testosterone replacement therapy. It starts at puberty and can spur on typical body changes, such as facial hair and a deeper voice. It can also help with penis size and stronger muscles and bones, but it won’t affect testicle size or fertility.
Testosterone replacement therapy throughout your life can help prevent some of the long-term problems that come with Klinefelter.

Other treatments may include:

  • Counseling and support for mental health issues
  • Fertility treatment (in some cases, using your own sperm to father a child)
  • Occupational and physical therapy to help with coordination and build muscles
  • Plastic surgery to reduce breast size
  • Speech therapy for children
  • Support in school to help with social skills and learning delays

If your child has Klinefelter, you can suggest that he:

  • Play sports and other physical activities to build muscles
  • Take part in group activities to learn social skill


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