Ataxin-1 is a member of the ATXN1 protein family and contains a single AXH domain. It is a neurodegenerative disorder protein thought to have a role in the metabolism of RNA as it has been shown to localize to the RNA and transcription dependent inclusions within the nucleus. A mutation of Ataxin-1 is the cause of spinocerebellar ataxia type-1 (SCA1), a progressive, neurodegenerative disease that is autosomal dominant and primarily affects the Purjinke cells found in brain stem neuronal populations and the cerebellum. Expression of Ataxin-1 is almost ubiquitous, except in the brain where it is isolated to populations of neurons.