Intrafamilial variability in SPTAN1-related disorder: From benign convulsions with mild gastroenteritis to developmental encephalopathy.

Mutations in SPTAN1 gene are responsible for a wide spectrum of neurodevelopmental disorders including early-onset epileptic encephalopathy with progressive brain atrophy, severe intellectual disability with cerebellar malformations, and relatively milder phenotypes with or without epilepsy. Herein, we report three affected individuals including two siblings of 13 and 8 years and their 39-year-old mother, carrying a novel pathogenic variant in SPTAN1 gene. The phenotype of the index cases and their mother was remarkable for the variable expressivity, including benign convulsions with mild gastroenteritis, intellectual disability and developmental encephalopathy with epilepsy. Our clinical observation suggests for the first time that variants in SPTAN1 gene might be involved in the aetiology of benign convulsions correlated with mild gastroenteritis.