Angelman syndrome usually has been considered to be rare and sporadic. However, recent reports suggest a sibling recurrence risk of just under 25 per cent, so early diagnosis is very important. The authors report Angelman syndrome in a child of seven months. The early features of this syndrome (jerky movements, EEG characteristics, chromosomal abnormalities in half the cases) should make it possible to diagnose or suspect the syndrome in the first year of life.