FURTHER EVIDENCE FOR DOMINANT INHERITANCE AT THE CHROMOSOME-15Q11-13 LOCUS IN FAMILIAL ANGELMAN SYNDROME

Eleven patients with Angelman syndrome (AS) and their parents from 5 families have been studied with high resolution chromosome analysis and molecular probes from region 15q11-13 in an attempt to elucidate the mode of inheritance in familial AS. No deletions were detected. All families were informative with a combination of different short arm cytogenetic markers. All sets of sibs inherited the same maternal chromosome 15, but in 3 families sibs inherited different paternal 15s. Analysis of 6 polymorphic DNA markers supported the conclusion that AS sibs inherit the same maternal 15, but often different paternal 15s. These data make autosomal recessive inheritance at a 15q11-13 locus very unlikely and support the hypothesis that familial AS is due to maternal transmission of a mutation within 15q11-13.