Klinefelter Syndrome

Overview

Klinefelter syndrome is a genetic disorder in which people assigned male at birth (AMAB) have an additional X chromosome in their genetic code. Most people AMAB have 46 chromosomes (packages of DNA). This includes one copy of an X chromosome and one copy of a Y chromosome (46, XY). People with Klinefelter syndrome have a total of 47 chromosomes (47, XXY).

Klinefelter syndrome is a congenital condition. That means you’re born with it. Symptoms vary significantly from person to person. You might receive a diagnosis early in life. But many people don’t even know they have the condition until adulthood, when symptoms like infertility come into play.

How common is Klinefelter syndrome?

Klinefelter syndrome is fairly common, occurring in about 1 in 600 people AMAB. But many people (some experts say 70% to 80%) likely don’t know they have this condition.

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Symptoms

When to see a doctor

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Complications

Blood clots are a dangerous complication of atrial fibrillation (AFib). Blood clots can lead to stroke.

The risk of stroke from AFib increases as you grow older. Other health conditions also may increase the risk of a stroke due to AFib. These conditions include:

High blood pressure.
Diabetes.
Heart failure.
Some types of heart valve disease.

Blood thinners are commonly prescribed to prevent blood clots and strokes in people with atrial fibrillation.

Prevention

Healthy lifestyle choices can reduce the risk of heart disease and may prevent atrial fibrillation (AFib). Here are some basic heart-healthy tips:

Control high blood pressure, high cholesterol and diabetes.
Don't smoke or use tobacco.
Eat a diet that's low in salt and saturated fat.
Exercise at least 30 minutes a day on most days of the week unless your health care team says not to.
Get good sleep. Adults should aim for 7 to 9 hours daily.
Maintain a healthy weight.
Reduce and manage stress.

By Mayo Clinic Staff

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Diagnosis & treatment

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