NF1 and Angelman syndrome: Eleven de novo results were confirmed out of a total of twelve where inheritance studies had been completed; six deletions of the chromosome 22q11 microdeletion/microduplication region, three abnormalities in the Prader Willi/Angelman syndrome region, one duplication of the Smith-Magenis region, one partial deletion of the Miller-Dieker region, one deletion of the NF1 region, one deletion of the Alagille region and one duplication of the Williams Beuren region.