Identification of a Japanese family with LRRK2 p.R1441G-related Parkinson's disease

Leucine-rich repeat kinase 2 (LRRK2) is a causative gene of autosomal dominant familial Parkinson's disease (PD). We screened for LRRK2 mutations in 3 frequently reported exons (31, 41, and 48) in our cohort of 871 Japanese patients with PD (430 with sporadic PD and 441 probands with familial PD). Direct sequencing analysis of LRRK2 revealed 1 proband (0.11%) with a p.R1441G mutation, identified for the first time in Asian countries, besides frequently reported substitutions including, the p.G2019S mutation (0.11%) and p.G2385R variant (11.37%). Several studies have suggested that the LRRK2 p.R1441G mutation, which is highly prevalent in the Basque country, is extremely rare outside of northern Spain. Further analysis of family members of the proband with the p.R1441G mutation revealed that her mother and first cousin shared the same mutation and parkinsonism. Haplotype analysis revealed a different haplotype from that of the original Spanish families. Our patients demonstrated levodopa-responsive parkinsonism with intrafamilial clinical heterogeneity. This is the first report of familial PD because of the LRRK2 p.R1441G mutation in Asia.