Triplication of SNCA is a rare cause of familial Parkinson's disease compared with duplication. Its clinical course is believed to be more robust than duplication, though it is uncertain. Marked as the first among the Asian population, we identified a Japanese family (paternal grandfather, father, and son) with SNCA triplication based on genetic and clinical analyses. The proband had a completely triplicated region including SNCA. This allele did not share any common haplotypes with those of previously reported Japanese families with SNCA duplication. Clinical analysis indicated early onset, rapidly progressive parkinsonism with mild levodopa response. Further studies are needed to clarify the gene dose effect of SNCA. © 2010 Movement Disorder Society