Phenotype of a child with Angelman syndrome born to a woman with Prader-Willi syndrome.

This report describes the phenotype, from early childhood to adolescence, of a girl with Angelman syndrome (AS) born following a maternal transmission of a germline paternal 15q11.2-q13 deletion. During early childhood, she showed a typical AS phenotype, such as jerky movements, poor sleep, high voltage electroencephalography pattern, epilepsy, and a severe developmental disability. As she grew older, indications of phenotypical traits similar to Prader-Willi syndrome (PWS) appeared, in particular hyperphagic behavior and a body fat distribution similar to that reported in PWS. She generally showed cheerful AS behavior and had the characteristic outbursts of laughter, but her attitude to other people did not reflect the usual shared enjoyment of interaction seen in children with AS. In unfamiliar surroundings, she withdrew socially, similar to children with PWS, and her insistence on the same, rigid routines was similar to behavior patterns in PWS. The dysmorphic facial features that characterize AS were blurred in adolescence. The specified features that this AS patient had in common with PWS were hardly incidental and, if verified by upcoming case reports of children born to women with a paternal 15q11.2-q13 deletion, they may show new aspects of genetic imprinting.