Early juvenile reading epilepsy and later frontotemporal dementia (FTD): expanding the clinical phenotype of C9ORF72 mutation?

Overview

C9orf72 mutation (C9⁺) is a common genetic cause of frontotemporal dementia and amyotrophic lateral sclerosis. C9⁺ clinical phenotype is heterogeneous and epilepsy has been recently described in few cases. We report a 47-year-old patient who developed reflex reading epilepsy (RRE) at the age of 19. After the first years with exclusive reflex seizures, afterwards the patients developed drug-resistant, unprovoked seizures and progressive cognitive deterioration. In the last years, a progressive motor impairment with spastic tetraparesis also occurred. During the hospitalization, the patient underwent an extensive workup identifying C9⁺ expansion and a family history suggestive for an autosomal dominant inheritance. This report, together with the few cases already described, raises the possibility that epileptic manifestations are part of the clinical phenotype of C9ORF72 mutation and reflect hyperexcitability of cortical networks involved in neurodegeneration.