Klinefelter Syndrome (KS)

What is Klinefelter Syndrome?

Klinefelter syndrome (KS) is also known as 47, XXY or XXY and describes the set of symptoms that are the consequence of two or more X chromosomes in males. The primary feature of Klinefelter syndrome is sterility. The condition is not inherited from one’s parents, occurs randomly, and the risk of developing Klinefelter syndrome is increased if the mother is older.

Those with the condition are usually of normal intelligence but do tend to develop reading difficulties and problems with speech. The genetic test known as karyotype is used to diagnose Klinefelter syndrome. In adult males lab tests such as hormone tests or a semen analysis is ordered in addition to the karyotype test. Klinefelter syndrome can be diagnosed before birth via genetic testing on the cells from the mother’s amniocentesis.

What are the Symptoms of Klinefelter Syndrome?

Some symptoms may be so subtle that the individual is unaware that they have the condition.

Prominent symptoms of Klinefelter syndrome include poor coordination, greater height, weaker muscles, less body hair, smaller genitals, breast growth, and less interest in sex which are noticed only during the onset of puberty.

Klinefelter Syndrome Causes

Klinefelter syndrome is not an inherited condition, as far as current research indicates. Instead, it seems to be the product of a random error, which causes a male child to be born with an extra sex chromosome. Out of the 46 chromosomes with which all humans are born, two chromosomes determine the sex of the individual. Females are born with two X chromosomes (XX) and males are born with one X and one Y chromosome (XY), but a baby born with Klinefelter syndrome has an additional X chromosome.

In common cases of the syndrome, the male child is born with one extra X chromosome in each cell, but there are cases where the duplicate X is only found in a few cells. This is called mosaic Klinefelter syndrome and presents fewer symptoms. In even rarer cases, there may be more than one duplicate X chromosome, but, where this does occur, the individual suffers from a more severe case of Klinefelter syndrome.

How is Klinefelter Syndrome Treated?

Males with Klinefelter syndrome should be given testosterone around the time of puberty for proper sexual development. It’s important to note that testosterone doesn’t help infertility in males. Testosterone can be delivered to the individual via gel, skin patch, or injection. Educational support and speech therapy is recommend for boys who have language or learning problems.

Klinefelter Syndrome Prevention

Since Klinefelter syndrome is a random occurrence with no known causal factors, there’s no way to prevent the condition from developing in a male child. The genetic mutation which causes this condition becomes more prevalent as mothers age. It has been found that women who become pregnant at 35 or older are at a greater risk of having a child with Klinefelter syndrome. Women older than 35 are encouraged to consult a doctor, before getting pregnant, to discuss the risks of conceiving a child with Klinefelter syndrome.

Males born with Klinefelter syndrome have a number of treatment options from testosterone replacement therapy to psychological counseling. Depending on how the symptoms develop, teen and pre-teen boys may need breast reduction surgery, speech therapy, and social support from parents, teachers, and counselors. Adult males may need to undergo fertility treatment, as Klinefelter syndrome reduces the level and quality of sperm produced in the testicles.

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