A total of 127 participants were included in this study: 46 patients with PD: 15 LRRK2-PD, 16 GBA-PD, and 15 iPD; and 81 non-manifesting (NM) first-degree relatives of PD patients: 47 NMC: 24 LRRK2-NMC, 23 GBA-NMC; and 34 NMNC. The gene discussed is LRRK2; the disease is Parkinson disease.