SNCA and Parkinson disease: That said, our exclusion criteria already removed patients known from prior testing to have monogenic forms of PD, and of the remaining 476 EOPD patients recruited in this study (comprising 15.6% of the study cohort)4,5,57,64,86,91,92, the vast majority (398 patients = 83.6%) underwent genotyping via NeuroBooster Array (NBA)93 and were found to be negative for pathogenic variants in SNCA, LRRK2, PRKN, PINK1, and PARK7/DJ-1.