| XYY syndrome | |
|---|---|
| Other names | 47,XYY[1] |
 | |
| Karyotype from a male with 47,XYY | |
| Specialty | Medical genetics |
| Symptoms | None, being taller than the parents, Mildly unusual physical features, severe acne, poor coordination, weak muscle tone, learning and speech problems[1][2] |
| Usual onset | At conception[3] |
| Duration | Lifelong |
| Causes | Two Y chromosomes in males[2] |
| Diagnostic method | Genetic testing[2] |
| Differential diagnosis | Klinefelter syndrome, Marfan syndrome, Sotos syndrome[2] |
| Prevention | None[4] |
| Treatment | Speech therapy, tutoring[2] |
| Prognosis | Normal life expectancy[2] |
| Frequency | ~1 in 1,000 males[1] |
XYY syndrome, also known as Jacobs syndrome, is an aneuploid genetic condition in which a male has an extra Y chromosome.[1] There are usually few symptoms.[2] These may include being taller than average and an increased risk of learning disabilities.[1][2] The person is generally otherwise normal, including typical rates of fertility.[1]
The condition is generally not inherited but rather occurs as a result of a random event during sperm development.[1] Diagnosis is by a chromosomal analysis, but most of those affected are not diagnosed within their lifetime.[2] There are 47 chromosomes, instead of the usual 46, giving a 47,XYY karyotype.[1]
Treatment may include speech therapy or extra help with schoolwork, however outcomes are generally positive.[2] The condition occurs in about 1 in 1,000 male births.[1] Many people with the condition are unaware that they have it.[4] The condition was first described in 1961.[5]
- ^ a b c d e f g h i "47,XYY syndrome". Genetics Home Reference. January 2009. Retrieved 2017-03-19.
- ^ a b c d e f g h i j "XYY Syndrome". NORD (National Organization for Rare Disorders). 2012. Retrieved 11 November 2017.
- ^ "XYY Syndrome".
- ^ a b "47, XYY syndrome". Genetic and Rare Diseases Information Center (GARD). 2017. Archived from the original on 11 November 2017. Retrieved 11 November 2017.
- ^ Bostwick, David G.; Cheng, Liang (2014). Urologic Surgical Pathology E-Book. Elsevier Health Sciences. p. 682. ISBN 978-0-323-08619-6.