A variant of the RAB32 gene is a risk factor for developing Parkinson disease (PD), according to a report published in Nature Genetics. Exome-wide analyses of 2,184 individuals with familial PD and 69,775 control individuals revealed that the p.S71R variant of RAB32 was present in around 0.7% of the PD group, compared with 0.004% of control individuals, and it segregated with PD in three families. RAB32 encodes a small GTPase that interacts with the PD-associated protein leucine-rich repeat kinase 2 (LRRK2), and the researchers showed that mutant RAB32 enhanced LRRK2 activity, which suggests a plausible mechanism through which the p.S71R variant could increase PD risk.