SCN2A- Associated Episodic and Persistent Ataxia with Cerebellar Atrophy: A Case Report.

SCN2A, a gene that codes for a sodium channel highly expressed in the cerebellum, has been linked to a heterogeneous phenotype, including episodic ataxia (EA) and epilepsy, among other symptoms1. Given the rarity of SCN2A-associated EA and its recent description, it is important the genotype-phenotype relationship of SCN2A-associated EA be better defined for prognosis and optimizing future management. Thus, we describe a 2-year-old boy with a SCN2A variant causing an initial prolonged episode of profound ataxia lasting 4 months, cerebellar atrophy, and persistent mild ataxia with episodic exacerbations. Due to the patient's lack of early epilepsy, prolonged initial episode of ataxia, and cerebellar atrophy, this case broadens the scope of the SCN2A variant phenotype. SCN2A should be considered as a cause of early onset ataxia in children with targeted testing or as part of Whole Exome Sequencing (WES) in patients with new onset persistent or EA with or without seizures.