Angelman/Prader-Willi Syndrome Methylation and Deletion/Duplication Analysis
Angelman syndrome is characterized by developmental delay/intellectual disability, speech impairment, ataxia, and unique behavior of inappropriate laughing, smiling, and excitability. Prader-Willi syndrome is characterized by hypotonia and feeding problems in infancy followed by excessive eating starting in early childhood, developmental delay, and mild intellectual disability. Methylation sensitive MLPA analysis is used to detect a deletion of the 15q11-q13 region and/or methylation defect. This testing identifies approximately 75% of individuals with Angelman syndrome (70% due to maternal deletion, 5% due to paternal UPD) and approximately 99% of individuals with Prader-Willi syndrome (70-75% due to paternal deletion, 25-29% due to maternal UPD).