Angelman syndrome is a genetic disorder. It's usually caused by problems with a gene located on chromosome 15 called the ubiquitin protein ligase E3A (UBE3A) gene.
A missing or defective gene
You receive your pairs of genes from your parents â one copy from your mother (maternal copy) and the other from your father (paternal copy).
Your cells typically use information from both copies, but in a small number of genes, only one copy is active.
Normally, only the maternal copy of the UBE3A gene is active in the brain. Most cases of Angelman syndrome occur when part of the maternal copy is missing or damaged.
In a few cases, Angelman syndrome is caused when two paternal copies of the gene are inherited, instead of one from each parent.