Klinefelter Syndrome

Klinefelter Syndrome is a condition in which males are born with an extra X chromosome, and the syndrome is sometimes referred to as XXY Syndrome. It affects approximately 1 in 500 males.  It is the most common sexual genetic disorder in males and is the most common form of hypogonadism (reduced ability of the testes to produce testosterone). This leads to a lack of secondary sex characteristics such as deepening of the voice and the inability to grow beard and body hair. It is almost always the case that adults will have small firm testicles, although over 50% have a normal sized penis.

Some men do not exhibit any symptoms while others will have enlarged breasts and sparse body hair. They can have a normal sex life but nearly all cannot father children. Studies have shown that females, who get pregnant after the age of 35, are slightly more at risk of a baby boy having Klinefelter Syndrome.

Males with Klinefelter Syndrome quite often have abnormal body proportions, e.g. short trunk, very long legs, and hip width the same as their shoulders. Some males have language and learning problems. Some severe effects of the syndrome include germ cell tumors, breast cancer and osteoporosis, loss of libido, erectile dysfunction and anemia. There may also be psychological effects also, such as attention deficit, limited verbalization and a failure to reach a family’s expectations at a career level.

Diagnosing Klinefelter Syndrome

The only reliable way to diagnose Klinefelter Syndrome is to do karyotype testing. This is a specialized procedure used to confirm the diagnosis. It involves taking a blood sample, separating the white blood cells and mixing them with tissue culture medium and then incubating (keeping the cells at a constant suitable temperature). After incubation the sample is then checked for any abnormalities. Diagnosis can also be carried out pre-natally by using a procedure called amniocentesis, (a tiny amount of fetal tissue is extracted and checked for any genetic abnormalities). By using IVF, (In Vitro Fertilization) over 120 successful pregnancies have been achieved by surgically extracting sperm material from men who have been diagnosed with Klinefelter Syndrome, so that is great news for those who wish to be a father.

Treatment for Klinefelter Syndrome

If at the time signs of puberty should be developing, but appear not to be, e.g. deepening ofthe voice, increased muscle mass, face and pubic hair growth, perhaps it is time to take your son to see a doctor and express your concerns. If diagnosed with Klinefelter Syndrome a course of testosterone therapy will be prescribed. This will go a long way to minimizing the syndrome, and provide a fairly normal quality of life. This is lifelong replacement therapy, and will be administered through injection every 2 weeks, or maybe gel, cream, or even a skin patch may be recommended.


The syndrome was named after Dr. Harry Klinefelter who first described it in 1942 in Boston U.S.A.  The first published report of a man with the XXY karyotype was in 1959 by Dr. Patricia A. Jacobs and Dr. J.A.Strong in Edinburgh, Scotland.

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