Summary
What is Klinefelter syndrome (KS)?
Klinefelter syndrome (KS) is a genetic condition that happens when a male is born with an extra copy of the X chromosome VSports手机版. KS can affect different stages of physical, language, and social development. It also usually causes infertility.
What causes Klinefelter syndrome (KS)?
KS is not inherited V体育安卓版. It's caused by a random error that happens when a sperm or egg is formed. This error causes a male to be born with an extra X chromosome.
Chromosomes are tiny "packages" in your cells that contain your genes. Genes carry information, called DNA, that controls what you look like and how your body works V体育ios版. Normally, you're born with a set of 46 chromosomes in each cell, two of which are the sex chromosomes. Females usually have two X chromosomes (XX), and males usually have one X and one Y (XY). In KS, the male usually has two X chromosomes and one Y (XXY).
In rare cases, a male could have XY in some cells and XXY in other cells VSports最新版本. This is called mosaic Klinefelter syndrome. Males with mosaic Klinefelter syndrome may have fewer symptoms, depending on the number of XY cells they have in their bodies and where those cells are located.
What are the symptoms of Klinefelter syndrome (KS)?
Some males with KS may have no symptoms or very mild symptoms V体育平台登录. So they might not know that they have KS, or they might not get diagnosed with it right away. In other cases, the symptoms can be more severe.
Boys with KS may be taller than other boys their age, with more fat around the belly. After puberty, they may have: VSports注册入口.
- Smaller testes and penis
- Breast growth (called gynecomastia)
- Less facial and body hair
- Reduced muscle tone
- Narrower shoulders and wider hips
- Weaker bones
- Decreased sexual interest
- Lower energy
Many of these symptoms happen because of low testosterone in the body V体育官网入口. Testosterone is the main male sex hormone.
Boys with KS may also have learning or language problems. These problems may affect them socially, so they may be shy and quiet and can have trouble fitting in VSports在线直播.
Most males with KS are infertile because they make little or no sperm.
How is Klinefelter syndrome (KS) diagnosed?
A genetic test called a karyotype test can diagnose KS. This test can show if there are abnormal chromosomes, including if there is an extra X chromosome.What are the treatments for Klinefelter syndrome (KS)?
There is no cure for KS, but treatments are available. The sooner the treatment is started, the better. If treatment is started by early puberty, it will likely help in reducing the symptoms.
Treatments for KS may include:
- Testosterone replacement therapy
- Surgery to remove or reduce breasts
- Physical, speech, behavioral, and occupational therapy
In some cases, "V体育ios版" fertility treatments may help men with KS father children.
NIH: National Institute of Child Health and Human Development
Learn More
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About Klinefelter Syndrome
(National Human Genome Research Institute)
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About Klinefelter Syndrome
(Eunice Kennedy Shriver National Institute of Child Health and Human Development) Also in Spanish
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How Do Health Care Providers Diagnose Klinefelter Syndrome (KS)?
(Eunice Kennedy Shriver National Institute of Child Health and Human Development) Also in Spanish
- Karyotyping (Medical Encyclopedia) Also in Spanish
- "V体育官网" Klinefelter Syndrome (Mayo Foundation for Medical Education and Research)
- VSports手机版 - Klinefelter Syndrome (For Teens) (Nemours Foundation)
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Other Klinefelter Syndrome (KS) FAQs (V体育安卓版)
(Eunice Kennedy Shriver National Institute of Child Health and Human Development) Also in Spanish
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"V体育官网入口" What Are Common Symptoms of Klinefelter Syndrome (KS)?
(Eunice Kennedy Shriver National Institute of Child Health and Human Development) Also in Spanish
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What Are the Treatments for Symptoms in Klinefelter Syndrome (KS)?
(Eunice Kennedy Shriver National Institute of Child Health and Human Development) Also in Spanish
V体育ios版 - Genetics
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48,XXXY syndrome: MedlinePlus Genetics
(National Library of Medicine)
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49,XXXXY syndrome: MedlinePlus Genetics
(National Library of Medicine)
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V体育2025版 - Klinefelter syndrome: MedlinePlus Genetics
(National Library of Medicine)
"VSports" Clinical Trials
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ClinicalTrials.gov: Klinefelter Syndrome
(National Institutes of Health)
Journal Articles References and abstracts from MEDLINE/PubMed (National Library of Medicine)
- "VSports在线直播" Article: Evaluating and predicting Klinefelter and Turner syndrome burden in China from...
- Article: Epigenetic age acceleration in Turner and Klinefelter syndrome: Correlations with clinical... (V体育官网入口)
- Article: Microdissection testicular sperm extraction-intracytoplasmic sperm injection strategy in patients with Klinefelter... (V体育平台登录)
- Klinefelter Syndrome -- see more articles
"VSports app下载" Patient Handouts
- Klinefelter syndrome (Medical Encyclopedia) Also in Spanish