Human SETX wild-type allele is located in the vicinity of 9q34.13 and is approximately 95 kb in length. This allele, which encodes probable helicase senataxin protein, plays a role in the metabolism of both DNA and RNA. Mutation of the gene is associated with juvenile amyotrophic lateral sclerosis 4 and autosomal recessive spinocerebellar ataxia 1. [ ]