Some LRRK2 mutations are relatively common; for instance, the G2019S variant is present worldwide and has a high prevalence in North Africa where it accounts for more than 30% of PD cases.3 Of note, LRRK2 mutations have an age‐dependent incomplete penetrance (ie, some individuals live until old age without any clinical signs of PD) and noncoding polymorphisms close to the LRRK2 locus can also act as risk factors for sporadic disease. This evidence concerns the gene LRRK2 and Parkinson disease.