Klinefelters syndrome

One of the most common genetic conditions affecting males, Klinefelter's syndrome is a genetic disorder in which males are born with an extra X chromosome. Individuals with Klinefelter's are often referred to as "XXY Males." Males are generally born with one X and one Y chromosome. This extra X chromosome can cause some unusual physical traits. Affecting roughly one out of every one thousand boys, this disorder is often undetectable until the individual reaches puberty, if it is even detected at all. 


The symptoms o Klinefelter's Syndrome depend on the age of the individual. The symptoms vary from person to person as well.

Symptoms of babies with Klinefelter's include:

  • No visible physical differences between young infants with Klinefelter's and healthy babies.
  • When the infant begins crawling, sitting up and walking, the muscles are weaker so it may take them longer to learn these basic motor functions.

Boys and teenagers may exhibit the following symptoms:

  • Boys may be taller, will have longer legs.
  • Will hit puberty later on than other boys.
  • Testicles will develop smaller and firmer than other boys.
  • Shyness, unassertive.
  • Less facial hair, less bodily hair.
  • Less muscular development.
  • Enlarged breast tissue.
  • Weaker bones.
  • Low energy levels.
  • Some boys may have language and learning problems/disabilities.

Men suffering from Klinefelter's may have the following symptoms:

  • Wide hips.
  • After puberty, the voice doesn't develop into a deeper tone.
  • Penis doesn't develop into adult size.
  • Testicles remain small.
  • Taller than average.
  • Majority of men suffering from Klinefelter's are infertile though they can engage in a normal sex life.


Klinefelter's is caused by some issue that occurs during sex cell division during the formation of the embryo. The extra X chromosome generally occurs as a result of the cells not splitting evenly when producing eggs. It can also occur if the cells split unevenly when producing sperm. Unlike other genetic disorders such as Down Syndrome that can be genetic, there has been nothing to prove that having a family history of Klinefelter's will lead to a child being born with the same disorder. Having a mother who is older is another factor that has been suspected but is not directly linked to Klinefelter's. 


Because the symptoms generally do not start to show themselves until the child enters puberty, Klinefelter's is usually not diagnosed until that time. The biggest signs that something may be wrong is the slow (or lack of) development of the testicles. Other symptoms such as learning disabilities, weak muscle and bones and low energy levels are also key indicators. If the parent or guardian suspects a disorder of some kind, a doctor will procure a family medical history, ask questions about past health and will administer a genetic test called a karyotype to determine any genetic abnormalities. Other tests the doctor will perform include a thorough medical examination and hormone testing.


Genetic abnormalities are irreversible. Unfortunately, there are no cures for Klinefelter's Syndrome although there are a number of medications that can be used to balance out the symptoms. The most common kinds of treatment are hormone replacement therapies. To balance out the hormone, testosterone, the individual may be given testosterone to help the individual develop as normally as possible. This hormone encourages hair growth, deepness of voice, helps lessen the development of breast tissue and helps the penis and testicles develop as normally as possible.