Angelman syndrome is due to

Most cases of Angelman syndrome are notinherited, paicularly those caused by a deletion in the maternal chromosome 15 or by paternal uniparental disomy. Thesegenetic changes occur as random events during the formation of reproductive cells (eggs and sperm) or in early embryonic development. Angelman syndrome was once known as'happy puppet syndrome' because of the child's sunny outlook and jerky movements. It is now called Angelman syndrome after Harry Angelman, the doctor who first investigated the symptoms in 1965. Refer robbins 172