Diseases

XXY Males (Klinefelter Syndrome) Information

Klinefelter syndrome facts*

Kleinfelter syndrome facts author: John P. Cunha, DO, FACOEP

• Klinefelter syndrome, also known as the XXY condition, is a term used to describe males who have an extra X chromosome in most of their cells.
• About one of every 500 males has an extra X chromosome, but many don't have any symptoms.
• Symptoms depend on how many XXY cells a man has, how much testosterone is in his body, and his age when the condition is diagnosed.
• As XXY males enter puberty, they may have a taller, less muscular body, less facial and body hair, and broader hips than other boys. As teens, XXY males may have larger breasts, weaker bones, and a lower energy level than other boys.
• XXY adult males look similar to males without the condition, although they are often taller and may have autoimmune disorders, breast cancer, vein diseases, osteoporosis, and tooth decay.
• XXY males can have normal sex lives, but they usually make little or no sperm and are infertile.
• The XXY chromosome pattern cannot be changed. Treatments involve physical, speech, occupational, behavioral, mental health, and family therapists, and testosterone replacement therapy (TRT).

Language development

As boys, it is not uncommon for XXY males have some kind of language problem, such as learning to talk late, trouble using language to express thoughts and needs, problems reading, and trouble processing what they hear. As adults, XXY males may have a harder time doing work that involves reading and writing, but most hold jobs and have successful careers.

Physical development

As babies, many XXY males have weak muscles and reduced strength. They may sit up, crawl, and walk later than other infants. After about age four, XXY males tend to be taller and may have less muscle control and coordination than other boys their age. As XXY males enter puberty, they often don't make as much testosterone as other boys. This can lead to a taller, less muscular body, less facial and body hair, and broader hips than other boys. As teens, XXY males may have larger breasts, weaker bones, and a lower energy level than other boys. By adulthood, XXY males look similar to males without the condition, although they are often taller. They are also more likely than other men to have certain health problems, such as autoimmune disorders, breast cancer, vein diseases, osteoporosis, and tooth decay. XXY males can have normal sex lives, but they usually make little or no sperm. Most XXY males are infertile because their bodies don't make a lot of sperm.

Social development

As babies, XXY males tend to be quiet and undemanding. As they get older, they are usually quieter, less self-confident, less active, and more helpful and obedient than other boys. As teens, XXY males tend to be quiet and shy. They may struggle in school and sports, meaning they may have more trouble "fitting in" with other kids. However, as adults, XXY males live lives similar to men without the condition; they have friends, families, and normal social relationships.