Febrile convulsions in selected large families: a single-major-locus mode of inheritance?

As part of a genetic linkage study of febrile convulsions, families with at least four members with the disorder were identified. By applying known principles of human inheritance, possible modes of transmission of febrile convulsions and factors which might impede progress in understanding their inheritance were analyzed. In eight families, 75 of 333 members had febrile convulsions. Inheritance of the disorder occurred in 43, 51, and 46% of children, siblings and all first-degree relatives of probands respectively. Vertical transmission occurred through three to four generations, including from male to male. In these families with multiple affected members, the findings support an autosomal dominant mode of inheritance of febrile convulsions.