For example, table 1 shows that 1% of white patients with sporadic PD and 3% with hereditary PD have the LRRK2 Gly2019Ser mutation, which means there is a prevalence of 3 cases per 100 000 people (estimate based on a PD prevalence of 200 cases per 100 000, and 15% of cases of PD are hereditary).19 This evidence concerns the gene LRRK2 and Parkinson disease.