Genotype-phenotype correlations in a group of 15 SCN1A-mutated italian patients with GEFS+ spectrum (seizures plus, classical and borderline severe myoclonic epilepsy of infancy)

Mutations in SCN1A gene have been associated with the spectrum of generalized/genetic epilepsy with febrile seizures plus. Recently, databases reporting SCN1A mutations and clinical details of patients have been created to facilitate genotype-phenotype correlations, actually not completely defined, particularly if a specific mutation underlies phenotypes. We report on a group of 15 patients with clinical features of GEFS+ (3), classical (7), or borderline severe myoclonic epilepsy of infancy (5), in whom genetic analysis of patients and parents and follow-up period were performed to establish genotype-phenotype correlations, to enrich literature and databases data. We found 11 pathogenic mutations (5 novel: c. 80 G>C exon 1; c. 187 T>C exon 1; c. 3061 G>T exon 16; c. 4297 G>A exon 22; c. 5579 delA ins TCTCC exon 26) and 4 novel nucleotidic variants (IVS5+38 C>T intron 5; IVS8-19 C>T intron 18; c. 4945 C>T exon 25; c. 5127 C>A exon 26). Paternal inheritance was observed in 4/4 cases.