Klinefelter Syndrome

Klinefelter Syndrome (KS) is a medical condition in which males are born with an extra X chromosome (rare diseases). Some males can have more than one extra X chromosome, which is known as variants of Kleinfelter Syndrome (Defendi). KS is not an inherited syndrome (RD). It occurs at random as the reproductive cells are forming, specifically during gametogenesis (RD, Defendi). Nondisjuncton, which is an error in cell division, can cause this abnormal number of chromosomes in the reproductive cells. If the effected reproductive cell goes on to contribute to the genetic makeup of the male, each body cell will have an extra or numerous extra X chromosomes (Defendi). It is the most common sex chromosome disorder, and occurs in approximately one in every 500-600 males (Defendi). It has not been found that any specific race has more or less of a predisposition for KS, and only males are effected (Defendi). The only identified risk factor for having offspring with KS is a maternal age of greater than 35 years old (Chang). Research has not shown any other ways to prevent KS, although early diagnosis and subsequent early interventions can be beneficial to the individual (RD).

The manifestations of KS differ greatly among affected individuals. Some may have no manifestations or may only be mildly affected. Those affected have varying degrees of physical symptoms, along with possible cognitive, behavioral, social, and learning difficulties (RD). Areas of communication and language are most often affected by the extra X chromosome (Defendi). Males with KS can have primary hypogonadism, meaning decreased testosterone levels (RD). This can present itself in numerous ways including gynecomastia, micropenis, decreased libido, infertility, along with small and/or undescended testes, known as cryptorchidism (Defendi). Other possible manifestations include a tall stature, decreased muscle mass and strength, decreased physical endurance, and a decrease in the amount of facial, pubic, axillary, or body hair (Defendi).

Most males are not diagnosed until adulthood, but researchers suspect that some males with KS are never diagnosed (Defendi, Chang). Diagnosis is often initiated based on clinical suspicion after assessment findings are consistent with the classic manifestations of KS (Chang). KS can be diagnosed by utilizing karyotype analysis, in which an individuals’ chromosomes are analyzed (Mayo). It can also be diagnosed using a urine or blood sample, in which hormone levels are examined (mayo). KS may be diagnosed before birth by examining the fetal cells from either the amniotic fluid or from the placenta (Mayo).

Treatment differs based on the symptoms and manifestations that each individual is experiencing (RD). Treatment is typically limited to testosterone replacement therapy, in which the goal is to reduce the complications caused by the hypogonadism (Chang). Males experiencing gynecomastia may get breast reduction surgery (RD). Several forms of therapy and educational intervention can be used to reduce symptoms sometimes associated with KS, such as speech impairments and learning difficulties (RD).

Due to the hypogonadism that can accompany KS, there is an increased risk for developing cardiovascular disease, metabolic syndrome, type 2 diabetes, breast cancer, and extragonadal germ cell tumors. Individuals with KS also have a higher risk of developing systemic lupus erythematosus, osterporosis, rheumatoid arthritis, and Sjogren Syndrome (Chang).