The clinical, electroencephalographic and genetic characteristics of Panayiotopoulos and Gastaut syndromes were explored, using twin and multiplex family studies, by researchers at The University of Melbourne, Australia, and Tel Aviv University, Israel. Sixteen probands including 7 twins were classified into early, late or mixed benign occipital epilepsy of childhood (BOEC) syndromes, and 9 non-twin probands with a family history of epilepsy were included. One-third of the children in this selected series of BOEC had a mixed syndrome with features of both Panayiotopoulos (early) and Gastaut (late) syndromes. Monozygotic twin pairs had a similar concordance rate to that of dizygotic twin pairs, suggesting that BOEC may not be a purely genetic disorder. A mixed pattern of focal and generalized epilepsies, mainly focal, was found in relatives with epilepsy. Panayiotopoulos and Gastaut syndromes are not distinct genetic entities, but part of an electro-clinical BOEC spectrum, with shared genetic and environmental determinants. 
COMMENT. The syndromes of Panayiotopoulos and Gastaut are not distinct, but part of a continuum of BOEC syndromes, with overlapping electro-clinical features, and largely undetermined, shared genetic and environmental factors in etiology. SCN1A missense mutation, identified with generalized epilepsy with febrile seizures plus and Dravet syndromes, has recently been reported in a family with atypical Panyiotopoulos syndrome.