We screened nine Italian families with generalized epilepsy with febrile seizures plus (GEFS+) for mutations in SCN1A, SCN1B, and GABRG2 genes (1–3). Probands were ascertained from the clinical practice in three epilepsy centers in southern Italy. Detailed family pedigrees were constructed, including maternal and paternal lines extending as far back as possible. In the nine families, we investigated 110 members of whom 37 individuals were determined to be affected. Most patients had febrile seizures (FSs) or FS plus (FS+) alone. A consistent number of patients also had only afebrile generalized seizures. Few patients had myoclonic seizures. One patient had a clinical picture of severe myoclonic epilepsy at infancy (SMEI).

Genomic DNA was extracted by standard methods. The 26 exons of SCN1A, five exons of SCN1B, and nine exons of GABRG2 were individually amplified by using primers based on an intronic sequence defined by comparison of cDNA (GenBank accession no. 043484). Polymerase chain reaction (PCR) products were analyzed by single-strand conformation polymorphism and sequence.