Although wild type ATXN1 is widely expressed, mutant ATXN1 (mATXN1) causes olivopontocerebellar atrophy with selective degeneration of Purkinje cells and neurons in the deep cerebellar nuclei, the brainstem and the spinal cord (Zoghbi, 1995; Klockgether, 2011). This evidence concerns the gene ATXN1 and olivopontocerebellar atrophy.