The Angelman or "happy puppet" syndrome. Clinical and electroencephalographic features and cerebral blood flow.

Two cases of happy puppet or Angelman syndrome are presented. They have the typical clinical features and represent the first Swedish cases. One of the patients is a man of 75 years of age, which shows that this form of severe mental retardation is well compatible with long life. Extended EEG monitoring may identify the typical EEG abnormality when this is difficult to demonstrate in routine EEG records. The typical laughter has no specific correlate in the EEG and thus is probably not an epileptic manifestation. Regional cerebral blood flow studies were normal in the young patient (11 years of age) but in the older patient showed a reduced cerebral circulation, compatible with organic dementia.