Does the phenotype depend on maternal inheritance?
Angelman’s syndrome was described by Angelman in 1965 and since then 222 children with the syndrome have been reported: this paper reviews the clinical and cytogenetic features of these children and describes three further children with the syndrome. About one half of the cases have a cytogenetically visible deletion involving the long arm of chromosome 15, del (15) (q11-q13). Thus the deletion is cytogenetically similar to the one found in some Prader-Willi syndrome patients, but it differs in parental origin, being maternal in Angelman’s syndrome and paternal in Prader-Willi’s syndrome. Perhaps then genomic imprinting has an important impact on the development of these very different phaenotypes. A new symptom is keratoconus. The Angelman syndrome is associated with ocular and general hypopigmentation and in future studies this should be included in the clinical examination, thereby elucidating the possible role of the proximal chromosome 15 in the development of the neural crest.
