This notwithstanding, together with the enrichment of the SYT10 gene region with SNPs that act as cis-eQTLs, our results suggest that genotype-specific regulation of SYT10 may be one of the factors modifying the effects of LRRK2 variation on PD risk and, to some extent, may thus explain the known reduced penetrance of p.G2019S. The gene discussed is LRRK2; the disease is Parkinson disease.