Four Novel SCN1A Mutations in Turkish Patients With Severe Myoclonic Epilepsy of Infancy (SMEI)

Severe myoclonic epilepsy of infancy (SMEI) (OMIM #607208), also known as Dravet syndrome, is a rare genetic disorder characterized by frequent generalized, unilateral clonic or tonic-clonic seizures that begin during the first year of life. Heterozygous de novo mutations in the SCN1A gene, which encodes the neuronal voltage-gated sodium channel α subunit type 1 (Nav1.1), are responsible for Dravet syndrome, with a broad spectrum of mutations and rearrangements having been reported. In this study, the authors present 4 novel mutations and confirm 2 previously identified mutations in the SCN1A gene found in a cohort of Turkish patients with Dravet syndrome. Mutational analysis of other responsible genes, GABRG2 and PCDH19, were unrevealing. The authors’ findings add to the known spectrum of mutations responsible for this disease phenotype and once again reinforce our understanding of the allelic heterogeneity of this disease.