- Happy puppet syndrome (formerly)
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Several different genetic mechanisms can inactivate or delete the maternal copy of the UBE3A gene. Most cases of Angelman syndrome occur when a segment of the maternal chromosome 15 containing this gene is deleted. In other cases, Angelman syndrome is caused by a mutation in the maternal copy of the UBE3A gene.
In a small percentage of cases, a person with Angelman syndrome inherits two copies of chromosome 15 from his or her father, instead of one copy from each parent. This is called paternal uniparental disomy. Rarely, Angelman syndrome can also be caused by a chromosomal rearrangement called a translocation, or by a mutation or other defect in the region of DNA that controls activation of the UBE3A gene. These genetic changes can abnormally turn off (inactivate) UBE3A or other genes on the maternal copy of chromosome 15.The cause of Angelman syndrome is unknown in 10 to 15 percent of affected individuals. Changes involving other genes or chromosomes may be responsible for the condition in these individuals.
- Angelman syndrome. Genetics Home Reference. May 2015; http://ghr.nlm.nih.gov/condition=angelmansyndrome.