The genetics of common epilepsies: common or distinct? In The Lancet Neurology, the International League Against Epilepsy Consortium on Complex Epilepsies

1reports the fi rst meta-analysis of genome-wide association studies (GWAS) in common epilepsies, following a route of large-scale collaborations familiar to many other groups of chronic diseases. The study brings together 12 separate datasets from three continents and diverse ethnic origins ranging from Chinese to Finnish. The analysis poses a philosophical question: can genetic factors be identifi ed when the 30 or so diff erent epilepsy syndromes are collapsed together or crudely considered as generalised or focal types? The results of the Consortium’s lumping strategy to investigate more than 2600 cases of generalised epilepsy and 5300 cases of focal epilepsy contain some