Recently, an expansion of AAGGG pentanucleotide repeats in intron 2 of the replication factor C subunit 1 (RFC1) gene has been identified as the genetic cause of cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS), a neurological disorder of autosomal recessive inheritance (4–7). The gene discussed is RFC1; the disease is nervous system disorder.