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Klinefelter Syndrome (KS)

KS describes a set of physical, language, and social development symptoms in males who have an extra X chromosome. Its main feature is infertility. Outward signs of KS can be subtle, so symptoms often are not recognized and may not be treated in a timely manner. NICHD is one of many federal agencies and NIH institutes working to understand KS, discover why it occurs, and identify and treat its symptoms.

Alternate Titles
XXY Syndrome