PRKN and Parkinson disease: Using age at onset (AAO) data from 5710 (87.1%) cases, we found that NeuroX PD cases with single PRKN mutations have significantly lower AAOs (average = 56.4 years) than cases without known mutations [average = 61.4 years; β-coefficient (Coeff) = −5.04; 95% CI: −8.32, −1.71; P = 0.003].