Klinefelter syndrome, sometimes referred to as XXY syndrome or 47,XXY is a genetic condition that affects males. Most males normally have one X and one Y chromosome; males that have Klinefelter syndrome have one extra copy of the X chromosome. This chromosomal abnormality can affect sexual development and cause other abnormalities. Klinefelter syndrome appears in about 1 in 750 males. More rare are particular variants of Klinefelter syndrome, in which the male has more than just one extra copy of the X chromosome.
Some men with the extra X chromosome present no symptoms and lead normal lives. Many others, however, may experience a variety of difficulties. Development of the sexual organs may not proceed normally. When the testicles do not develop normally, affected males will likely have lower levels of testosterone. A lack of testosterone can create breast development, infertility, and reduced facial and body hair.
Other problems caused by Klinefelter syndrome can include delayed speech and language development, delayed emotional development, behavioral problems, and increased risk of breast cancer and systemic lupus erythematosus, a chronic inflammatory disease.
Cases in which the male has more than just one extra copy of the X chromosome may cause more severe disabilities, including learning delays, sexual dysfunction, and distorted facial features.
Klinefelter syndrome is not passed on from parent to child. Instead, it typically occurs as the result of an error in the process of cell division that produces sperm or egg. There are no known ways to predict whether this error will occur. Prenatal testing does not typically include screening for Klinefelter syndrome.
Klinefelter Syndrome is typically diagnosed as a boy enters puberty. Early diagnosis can assist greatly, as any social and developmental problems can be addressed sooner, and appropriate educational interventions can be determined.
The primary treatment for Klinefelter syndrome includes hormone replacement. Treatment of the symptoms of Klinefelter Syndrome may, for example, include speech therapy for speech and language delays, or counseling and social skills training for behavioral problems.