Expanding phenotype of PRRT2 gene mutations: A new case with epilepsy and benign myoclonus of early infancy.

Abstract

Mutations in the gene PRRT2 have been identified in a variety of early-onset paroxysmal disorders. To date associations between PRRT2 mutations and benign myoclonus of early infancy have not been reported. We describe a baby affected by PRRT2 mutation and benign infantile epilepsy, with an episode of focal status epilepticus. During follow-up he developed benign myoclonus of early infancy. We hypothesize a pathogenic role of PRRT2 mutation in inducing benign myoclonus of early infancy, similarly to that at the origin of other PRRT2-related paroxysmal movement disorders, such as paroxysmal kinesigenic dyskinesia. Currently the function of PRRT2 is poorly understood, even if a marked pleiotropy and variable penetrance of its mutations are well known. Our case concurs in expanding the broad clinical spectrum of PRRT2-related disorders.