Diagnosis of Angelman syndrome: clinical and EEG criteria

In order to evaluate which diagnostic criteria can be indicative for an ear ly diagnosis of Angelman syndrome (AS), 144 children with severe epilepsy a nd mental retardation were evaluated. In 10 of them the diagnostic criteria indicated by Williams were present. Of the remaining 134 patients we were able to diagnose one 15-year-old patient with AS, on the basis of the EEG f indings, even though the typical clinical features of the syndrome were abs ent. In all patients the diagnosis of AS was confirmed by fluorescent in si tu hybridization (FISH) in 10 patients and by methylation analysis in one p atient. AS is very likely when both typical clinical and EEG findings are p resent. Nevertheless, it must be considered in all patients affected by sev ere epilepsy and mental retardation, when the EEG pattern is sufficiently i ndicative, and FISH and/or molecular analysis should be performed even in a bsence of typical clinical signs. (C) 1999 Elsevier Science B.V. All rights reserved.