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NORD is very grateful to Professor Rhoshel K. Lenroot, MD, Chair of Infant, Child, and Adolescent Psychiatry, University of New South Wales; Director of Child and Adolescent Mental Health Services, South Eastern Sydney Local Health District; Neuroscience Research Australia (NeuRA), for assistance in the preparation of this report.
Synonyms of XYY Syndrome
- 47, XYY syndrome
- Jacob's syndrome
- XYY karyotype
- YY syndrome
- No subdivisions found.
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.
Organizations related to XYY Syndrome
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