Two Cases of Autosomal Recessive Spinocerebellar Ataxia-8 Showing Two Novel Variants of SYNE1 in Japanese Families

Autosomal recessive spinocerebellar ataxia-8 (SCAR8) is a neurodegenerative disorder caused by the biallelic pathogenic variants of SYNE1. It is characterized by slowly progressive cerebellar ataxia and atrophy. We identified two SCAR8 families using exome analyses and two novel variants, c.2127delG (p.Met709Ilefs) and c.15943G>T (p.Gly5315*), in SYNE1 (NM_182961.4). Pathogenic variants of SYNE1 cause various symptoms, including cerebellar ataxia, pyramidal tract disorders, and joint disorders, and the pathogenic variants discovered in this study were located in a region prone to cerebellar ataxia.