Munson Health
Klinefelter Syndrome

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by Rosenblum L

(47 XXY Syndrome; KS)



A test called a karyotype is used to diagnose KS. In the case of KS, there are usually 47 chromosomes rather than the normal 46.
Many men with XXY do not know they have the condition. The diagnosis may be found:
  • When amniocentesis is done
  • In babies— with undescended testes or very small penis
  • In children—when the child is having problems learning
  • In adolescents—when the child has delayed puberty or excessive breast development
  • In adults—when the man has fertility concerns


Klinefelter Syndrome and Associates

National Institute of Child Health & Human Development



Canadian Psychiatric Association

Canadian Psychological Association



Klinefelter syndrome. EBSCO DynaMed website. Available at: . Updated February 28, 2013. Accessed October 11, 2011.

Tell me about 47, XXY. Klinefelter Syndrome and Associates website. Available at: . Accessed August 20, 2013.

Klinefelter syndrome: overview. National Institute of Child Health & Human Development website. Available at: . Updated April 3, 2013. Accessed August 20, 2013.


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