National Organization for Rare Disorders, Inc.
It is possible that the main title of the report XYY 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.
XYY syndrome is a rare chromosomal disorder that affects males. It is caused by the presence of an extra Y chromosome. Males normally have one X and one Y chromosome. However, individuals with this syndrome have one X and two Y chromosomes. Affected individuals are usually very tall. Many experience severe acne during adolescence. Additional symptoms may include learning disabilities and behavioral problems such as impulsivity. Intelligence is usually in the normal range, although IQ is on average 10-15 points lower than siblings.
In the past, there were many misconceptions about this disease. It was sometimes called the super-male disease because men with this syndrome were thought to be overly-aggressive and lacking in empathy. Recent studies have shown that this is not the case. Although individuals with XYY syndrome have an increased risk for learning disabilities and behavioral problems, they are not overly aggressive, nor are they at an increased risk of any serious mental illness. Because these boys are at a higher risk for having learning disabilities, they may benefit from speech therapy, tutoring, and general awareness of the specific issues they struggle with. Although the first years of school may be more challenging for boys with XYY syndrome, they generally go on to lead full, healthy, and normal lives.
March of Dimes Birth Defects Foundation
1275 Mamaroneck Avenue
White Plains, NY 10605
National Mental Health Consumers' Self-Help Clearinghouse
1211 Chestnut Street
Philadelphia, PA 19107-6312
Mental Health America
2000 N. Beauregard Street, 6th Floor
Alexandria, VA 22314-2971
National Alliance on Mental Illness
3803 N. Fairfax Drive
Arlington, VA 22203-
NIH/National Institute of Mental Health
Health Science Writing, Press and Dissemination Branch
6001 Executive Boulevard
Room 8184, MSC 9663
Bethesda, MD 20892-9663
UNIQUE - Rare Chromosome Disorder Support Group
P.O. Box 2189
Surrey, CR3 5GN
Genetic and Rare Diseases (GARD) Information Center
PO Box 8126
Gaithersburg, MD 20898-8126
Klinefelter Syndrome & Associates
P.O. Box 872
Pine, CO 80470-0872
Focus Foundation, Inc.
PO Box 190
Davidsonville, MD 21035
For a Complete Report
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.
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Last Updated: 10/3/2012
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