It is regarded as the most common subtype of spinocerebellar ataxias (SCAs) in China3 and is caused by a pathological expansion of cytosine‐adenineguanine (CAG) trinucleotide repeats in exon10 of the ATXN3 gene located in Chr 14q32.1, which results in the production of an abnormal expansion of polyglutamine repeats in the ataxin‐3 protein.4, 5. The gene discussed is ATXN3; the disease is cerebellar ataxia.