Angelman syndrome (happy puppet syndrome)
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Genetics
- genetically heterogeneous group
- most cases are sporadic but familial cases have been reported[1]
- 60-70% of cases are due to an interstitial deletion on the maternally inherited chromosome 15 in the region q11-q13*
- rare cases result from paternal disomy
- in 30% of patients, neither maternal inherited deletion, nor paternal disomy, can be found
- associated with defects in MECP
- associated with defects in ATP10A
*The Prader-Willi syndrome (PWS) & the Angelman syndrome (AS) are 2 clinically distinct disorders that are caused by a differential parental origin of chromosome 15q11-q13 deletions. Both also can result from uniparental disomy (the inheritance of both copies of chromosome 15 from only one parent). Loss of the paternal copy of 15q11-q13, whether by deletion or maternal uniparental disomy, leads to PWS, whereas a maternal deletion or paternal uniparentaldisomy leads to AS.
The differential modification in expression of certain mammalian genes dependent upon parental origin is known as genomic imprinting, and AS and PWS represent the best examples of this phenomenon in humans. Although the molecular mechanisms of genomic imprinting are unknown, DNA methylation has been postulated to play a role in the imprinting process.
Clinical manifestations
- severe mental retardation
- easily provoked laughter
- ataxia
- absent speech
- seizures
More general terms
More specific terms
Additional terms
References
- ↑ 1.0 1.1 Moncla et al Archives de Pediatrie 1(12):1118-26, 1994
- ↑ Saitoh Am J Med Genetics 52(2):158-63, 1994
- ↑ NINDS Angelman Syndrome Information Page https://www.ninds.nih.gov/Disorders/All-Disorders/Angelman-Syndrome-Information-Page
- ↑ ARUP Consult: Angelman Syndrome and Prader-Willi Syndrome The Physician's Guide to Laboratory Test Selection & Interpretation https://www.arupconsult.com/content/prader-willi-syndrome
Angelman Syndrome and Prader-Willi Syndrome Testing https://arupconsult.com/ati/angelman-syndrome-and-prader-willi-syndrome-testing
Patient information
Angelman syndrome patient information