Rare lysosomal enzyme gene SMPD1 variant (p.R591C) associates with Parkinson's disease.

To investigate the role of mutations in the sphingomyelin phosphodiesterase (SMPD1) gene in Parkinson's disease (PD) we sequenced all the exons of this gene in 198 Chinese PD cases and matched healthy control subjects. We identified 4 rare variants in SMPD1 (p.P332R, p.Y500H, p.P533L, and p.R591C) that were present only in cases and not in control subjects. Interestingly, 2 of these variants were previously reported in Chinese Niemann-Pick disease patients. Next, we genotyped these variants in another 806 PD cases and 7481 control subjects. We identified a novel, rare SMPD1 variant (p.R591C) which increased the risk of PD (p = 0.009).