National Organization for Rare Disorders, Inc.
It is possible that the main title of the report Klinefelter Syndrome is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.
Synonyms Back to top
- XXY male
- XX male
- XXYY male
- XXXY male
- XXXXY male
Disorder Subdivisions Back to top
General Discussion Back to top
Klinefelter syndrome is a group of chromosomal disorders in males in which one or more extra X chromosomes are present. Males with the classic form of the disorder have one extra X chromosome. Males with variant forms of Klinefelter syndrome have additional X and/or Y chromosomes. The extra X and/or Y chromosome can affect physical, developmental, behavioral, and cognitive functioning. Common physical features may include tall stature, lack of secondary pubertal development, small testes (hypogonadism), delayed pubertal development, and breast development (gynecomastia) in late puberty. These features may be associated with low testosterone level and elevated gonadotropin levels.
Resources Back to top
March of Dimes Birth Defects Foundation
1275 Mamaroneck Avenue
White Plains, NY 10605
870 Miranda Green
Palo Alto, CA 94306
Klinefelter Syndrome Association of Canada
42 Ritson Road South, Upper floor,
Ontario, L1H 5G9
NIH/National Institute of Child Health and Human Development
31 Center Dr
Building 31, Room 2A32
Bethesda, MD 20892
American Association for Klinefelter Syndrome Information and Support
c/o Roberta Rappaport
2945 W. Farwell Avenue
Chicago, IL 60645-2925
MUMS National Parent-to-Parent Network
150 Custer Court
Green Bay, WI 54301-1243
Klinefelters Syndrome Support Group of Australia
New South Wales, 2155
Tel: 04 25240773
PO Box 460265
Aurora, CO 80046-0628
Genetic and Rare Diseases (GARD) Information Center
PO Box 8126
Gaithersburg, MD 20898-8126
PO Box 241956
Los Angeles, CA 90024
Klinefelter Syndrome & Associates
P.O. Box 461047
Aurora, CO 80046-1047
Focus Foundation, Inc.
PO Box 190
Davidsonville, MD 21035
For a Complete Report Back to top
This is an abstract of a report from the National Organization for Rare Disorders (NORD). A copy of the complete report can be downloaded free from the NORD website for registered users. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational therapies (if available), and references from medical literature. For a full-text version of this topic, go to www.rarediseases.org and click on Rare Disease Database under "Rare Disease Information".
The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only. NORD recommends that affected individuals seek the advice or counsel of their own personal physicians.
It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report
This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.
For additional information and assistance about rare disorders, please contact the National Organization for Rare Disorders at P.O. Box 1968, Danbury, CT 06813-1968; phone (203) 744-0100; web site www.rarediseases.org or email email@example.com
Last Updated: 6/13/2011
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