Genetics Home > Adolescents With Klinefelter Syndrome
Adolescents with Klinefelter syndrome may have a more difficult time in high school than others. Symptoms like gynecomastia, lack of athletic ability, and language difficulties can make these adolescents the target of ridicule and scorn by students who do not understand. Adolescents with Klinefelter syndrome may benefit from counseling. Also, regular testosterone injections beginning at puberty may help alleviate certain physical symptoms.
In general, boys with Klinefelter syndrome enter puberty normally, without any delay of physical maturity. But as puberty progresses, they fail to keep pace with other males. In chromosomally normal teenaged boys, the testes gradually increase in size, from an initial volume of about 2 mL, to about 15 mL. In males with Klinefelter syndrome, while the penis is usually of normal size, the testes remain at 2 mL, and cannot produce sufficient quantities of the male hormone testosterone. As a result, many XXY adolescents, although taller than average, may not be as strong as other teenaged boys and may lack facial or body hair.
As they enter puberty, many boys will undergo slight breast enlargement. For most teenaged males, this condition, known as gynecomastia, tends to disappear in a short time. About one third of boys with Klinefelter syndrome develop enlarged breasts in early adolescence -- slightly more than average number of chromosomally normal boys who do. Furthermore, in boys with Klinefelter syndrome, this condition may be permanent. However, only about 10 percent of males with Klinefelter syndrome have breast enlargement great enough to require surgery.