Genetic and clinical features of cerebellar ataxia with biallelic repeat expansions in Japan.

The recessive intronic pentanucleotide repeat AAGGG expansion of replication factor complex subunit 1 () is associated with cerebellar ataxia, sensory neuropathy, and vestibular areflexia syndrome. And the clinical spectrum has been continuously expanding. We conducted this study to demonstrate the clinical and genetic features of a large-scale case series of Japanese patients with cerebellar ataxia with repeat expansions.