Definition

Klinefelter syndrome (KS) happens in men who have more than one X chromosome (XXY).

Klinefelter Syndrome Copyright © Nucleus Medical Media, Inc.

Causes

Males have a single X chromosome from their mother and a single Y one from their father. Males with KS get at least one extra X from either parent.

Risk Factors

There are no known risk factors for KS.

Symptoms

Symptoms may not be found until puberty or later.

Children may have problems with:

• Speech
• Learning
• Behavior

Teens may have:

• Delayed puberty
• Enlarged breasts

Adults may have:

• Small, firm testes
• Small penis
• A poor sex drive or sexual problems
• Lack of facial and body hair
• Breast pain
• Hot flashes, sweating

Diagnosis

The doctor will ask about your symptoms and health history. A physical exam will be done.

KS is diagnosed with a genetic test. Blood tests may also be done.

Treatment

There is no cure. The goal is to manage symptoms. Choices are:

• Testosterone therapy to raise low levels of this hormone
• Speech and language therapy
• Special education services
• Mental health counseling

Prevention

There are no known guidelines to prevent KS.