Objective The frequency of autosomal dominant cerebellar ataxia (ADCA) varies between different regions of Japan. This is the first report on the prevalence of ADCA subtypes in Aomori, Japan. Methods and Patients Sixty-five familial spinocerebellar ataxia (SCA) patients and 15 sporadic SCA patients were genetically examined. For only the SCA2 patients (n = 8), the magnetic resonance imaging (MRI) data were analyzed in detail. Results Spinocerebellar ataxia (SCA) type 6 was often observed (77.7% of cases), with SCA2 (10.6% of cases) being the next most common form. In contrast, only one of the eighty patients had SCA1. Among the 15 sporadic SCA patients, genetic mutations for SCA2, SCA6, SCA17, and SCA31 were identified, indicating that ADCAs should be considered in sporadic cases of ataxia. Furthermore, in SCA2 cases, brainstem atrophy, pontine midline linear hyperintensity, and atrophy of the frontal lobes were frequently observed using MRI. Conclusion The present data indicate that the prevalence of ADCA in Aomori differs from other prefectures in the Tohoku District. MRI findings are very similar between SCA2 and multiple system atrophy (MSA), and thus care must be taken to prevent the misdiagnosis of sporadic SCA2 as MSA.

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