Klinefelter's syndrome

Klinefelter's syndrome: a condition identified by a chromosomal anomaly in morphologic males with the pathognomonic symptoms of a small penis, small testes, sterility, and in some cases gynecomastia. The basic genetic defect is an extra sex chromosome with a total count of 47,XXY. Variants of the syndrome are characterized by more than one extra X chromosome, e.g., 48,XXXY. The secondary sex characteristics are usually weakly developed and do not respond well to treatment with male sex hormone.

Dictionary of Sexology Project: Main Index

What is Klinefelter's Syndrome?

Klinefelter's Syndrome is a genetic disorder first discoverd by Harry Klinefelter in 1942. It is caused by an extra X chromosome in a male.

What Are the Symptoms? Can it be Cured?

Symptoms of Klinefelter's Syndrome include: occasional breast enlargement, a lack of facial and/or body hair, a rounded body type, and infertility. Klinefelter's Syndrome is not fatal and cannot be cured, however, the effects can be lessened with testosterone injections starting anytime after the onset of puberty.

How Does it Happen?

During meiosis the X chromosomes in females, or the X and Y chromosomes in males, do not pair or exchange genetic material. This occasionally results in both chromosomes moving to the same cell. This produces either and ovum with two X chromosomes, or a sperm with both an X and Y chromosome. When a double X ovum is fertilized by a normal sperm, or an XY sperm fetilizes a normal ovum, an XXY male is conceived.

Could it Happen to Us?

Klinefelter's Syndrome is diagnosed in about 1 in 500 to 1 in 1000 men. It can be diagnosed by amniocentesis, at adolescence with medical assistance, and in adulthood with infertility tests.