The Angelman ('happy puppet') syndrome is clinically characterized by severe mental retardation without any development of speech, a happy disposition with paroxysms of laughter, a stiff-atactic gait with arms in flexion and abduction, epileptic seizures, EEG-abnormalities, and some dysmorphic features like prognathism, macrosomia, tongue protrusion and brachycephaly and/or microcephaly. The genetic background is still obscure, but in some patients with this syndrome small deletions in the long arm of chromosome 15 have been found. So further investigation of this probably rather frequent syndrome seems appropriate.