Breath samples, collected from 73 PD patients, encompassing both genetic (LRRK2: n = 12, GBA1: n = 35, PRKN: n = 6) and idiopathic PD (n = 20), 4 unaffected LRRK2 pathogenic variant carriers, and 90 controls underwent extreme-resolution FT-ICR-MS analysis. The gene discussed is LRRK2; the disease is Parkinson disease.