Klinefelter's disease, also known as Klinefelter's syndrome or XXY male, refers to a common genetic disorder where males have an extra X chromosome (genetic material) in each of their cells. According to the Mayo Clinic, Klinefelter's syndrome can be diagnosed before birth with genetic testing or during childhood. The National Institute of Child Health and Human Development (NICHHD) states that 1 out of every 500 males in the United States have Klinefelter's syndrome.
Abnormal Physical Development
According to the NICHHD, physical symptoms vary with age. Male babies have weaker muscles and may and crawl and walk at later ages. The Mayo Clinic states that male boys or teenagers are taller and experience delayed puberty. During puberty, these males may have smaller testicles, produce less testosterone and develop breasts as a result. Breast development in males is called gynecomastia.
Reserved Personality
Males with Klinefelter's syndrome tend to be reserved, according to the NICHHD. Babies tend to be quiet and less fussy. As boys, they may be quieter, lack self-confidence and tend to be obedient. Teenage males may struggle to form friendships and find a niche. Adults with Klinefelter's syndrome may outgrow this and are as able to form friendships and relationships as men without Klinefelter's syndrome.
Infertility
The Mayo Clinic states that men with Klinefelter's syndrome are unable to produce enough sperm to create a child. This is due to their decreased amounts of testosterone and small testicles. However, new treatments are available so that men with Klinefelter's syndrome can father children.
Language Problems
According to the NICHHD, males with Klinefelter's syndrome can have speech problems, trouble reading and trouble understanding what is said to them.
