What is the probability of inheriting angelman syndrome?

Actually, : It's almost always a new mutation. If mom has a translocation on chromososome 15 or has a point mutation of the ube3a gene, the risk goes up. It can be from deletion of 15q11-q13 on the maternal copy of chromosome 15 or from having both chromosomes 15 come from father or act as if they're both from father.Fish test of chr 15 or cgh & methylation are genetic tests used for diagnosis & to test mom.