Klinefelter's Syndrome Support Group

XXY males are almost always sterile, and some degree of language impairment may be present. In adults, possible characteristics vary widely and include little to no signs of affectedness, a lanky, youthful build and facial appearance, or a rounded body type with some degree of gynecomastia (increased breast tissue). Gynecomastia to some extent is present in about a third of individuals affected, a higher percentage than in the XY population. The far end of the spectrum is also associated with an increased risk of breast cancer, pulmonary disease, varicose veins, and osteoporosis, risks shared with women.

Rare X-linked recessive problems occur even more infrequently in XXY males, since these conditions are transmitted by genes on the X chromosome, and people with two X chromosomes are typically carriers rather than affected.

There are many variances within the XXY population, just like in the 46,XY population. While it is possible to characterise 47,XXY males with certain body types, that in itself should not be the method of identification as to whether someone has 47,XXY or not. The only method of identification is karyotype testing.

The condition is irreversible, but its symptoms can be altered in a number of ways, including testosterone treatment and other therapies.

While the gender identity of people with XXY karyotype is generally stable, the number of people with gender identity disorder among the whole seems to be higher than could statistically be expected if those cases were indeed, as the current medical opinion assesses, mere coincidences of people having both gender identity disorder and Klinefelter's independently from each other. The observation on gender identity is based on the reports of support groups for transgender and transsexual people; no scientific study on this subject has been done. The fact that a person undergoing treatment for gender identity disorder has Klinefelter's syndrome is often missed, or the patient is not told, although in many jurisdictions this additional diagnosis can have legal consequences, for example regarding name change or medical treatment having to be adapted.