Skip navigation
   Other Topics: A B C D E F G H I J K L M N O P Q R S T U V W XYZ All Topics

Klinefelter's Syndrome

Also called: XXY male 
 
 

Klinefelter's syndrome (KS) is a condition that occurs in men who have an extra X chromosome. The syndrome can affect different stages of physical, language, and social development.

The most common symptom is infertility. Boys may be taller than other boys their age, with more fat around the belly. After puberty, KS boys may have

  • Smaller testes and penis
  • Breast growth
  • Less facial and body hair
  • Reduced muscle tone
  • Narrower shoulders and wider hips
  • Weaker bones
  • Decreased sexual interest
  • Lower energy

KS males may have learning or language problems. They may be quiet and shy and have trouble fitting in.

A genetic test can diagnose KS. There is no cure, but treatments are available. It is important to start treatment as early as possible. With treatment, most boys grow up to have normal lives.

Treatments include testosterone replacement therapy and breast reduction surgery. If needed, physical, speech, language, and occupational therapy may also help.

NIH: National Institute of Child Health and Human Development

 

 

 
 
Basics Learn More Multimedia & Cool Tools

 

 
Research Reference Shelf For You

 

 

 

Illustration of chromosomes and DNA

Related Topics

National Institutes of Health

 

  • MedlinePlus links to health information from the National Institutes of Health and other federal government agencies. MedlinePlus also links to health information from non-government Web sites. See our disclaimer about external links and our quality guidelines.

 

 

 

MedlinePlus links to health information from the National Institutes of Health and other federal government agencies. MedlinePlus also links to health information from non-government Web sites. See our disclaimer about external links and our quality guidelines.