Multiple system atrophy: clinicopathological characteristics in Japanese patients

Multiple system atrophy (MSA) is an adult-onset neurodegenerative disorder that has both clinical and pathological variants. Clinical examples include MSA with predominant cerebellar ataxia (MSA-C) and MSA with predominant parkinsonism (MSA-P), whereas olivopontocerebellar atrophy and striatonigral degeneration represent pathological variants. We performed systematic reviews of studies that addressed the relative frequencies of clinical or pathological variants of MSA in various populations to determine the clinicopathological characteristics in Japanese MSA. The results revealed that the majority of Japanese patients have MSA-C, while the majority of patients in Europe and North America have MSA-P. A comparative study of MSA pathology showed that the olivopontocerebellar-predominant pathology was more frequent in Japanese MSA than in British MSA. Demonstrated differences in pathological subtype thus appear consistent with differences in the clinical subtype of MSA demonstrated between Japan and European populations. We concluded that olivopontocerebellar-predominant pathology and MSA-C may represent clinicopathological characteristics in Japanese MSA. Factors determining predominant involvement of olivopontocerebellar regions in MSA should therefore be explored.