A genetic condition in which a male is born with an extra copy of the X chromosome
Klinefelter’s syndrome isn’t inherited, but rather occurs only as a result of a random genetic error after conception.
Klinefelter syndrome may adversely affect testicular growth, resulting in smaller than normal testicles, which can lead to lower production of testosterone. The syndrome may also cause reduced muscle mass, reduced body and facial hair, and enlarged breast tissue. The effects of Klinefelter syndrome vary, and not everyone has the same signs and symptoms.Most men with Klinefelter syndrome produce little or no sperm, but assisted reproductive procedures may make it possible for some men with Klinefelter syndrome to father children.
Symptoms
Signs and symptoms of Klinefelter syndrome vary widely among males with the disorder. Many boys with Klinefelter syndrome have few noticeable signs, and the condition may go undiagnosed until adulthood. For others, the condition has a noticeable effect on growth or appearance.
Signs and symptoms of Klinefelter syndrome also vary by age.
Babies
Signs and symptoms may include:
- Weak muscles
- Slow motor development — taking longer than average to sit up, crawl and walk
- Delay in speaking
- Quiet, docile personality
- Problems at birth, such as testicles that haven’t descended into the scrotum
Boys and teenagers
Signs and symptoms may include:
Taller than average stature
Longer legs, shorter torso and broader hips compared with other boys
Absent, delayed or incomplete puberty
After puberty, less muscle and less facial and body hair compared with other teens
Small, firm testicles
Small penis
Enlarged breast tissue (gynecomastia)
Weak bones
Low energy levels
Tendency to be shy and sensitive
Difficulty expressing thoughts and feelings or socializing
Problems with reading, writing, spelling or math
Men
Low sperm count or no sperm
Small testicles and penis
Low sex drive
Taller than average height
Weak bones
Decreased facial and body hair
Less muscular than normal
Enlarged breast tissue
Increased belly fat
One common treatment is testosterone replacement therapy. It starts at puberty and can spur on typical body changes, such as facial hair and a deeper voice. It can also help with penis size and stronger muscles and bones, but it won’t affect testicle size or fertility.
Treatment
Testosterone replacement therapy throughout your life can help prevent some of the long-term problems that come with Klinefelter.
Other treatments may include:
Counseling and support for mental health issues
Fertility treatment (in some cases, using your own sperm to father a child)
Occupational and physical therapy to help with coordination and build muscles
Plastic surgery to reduce breast size
Speech therapy for children
Support in school to help with social skills and learning delays
If your child has Klinefelter, you can suggest that he:
Play sports and other physical activities to build muscles
Take part in group activities to learn social skills
