GBA1 and Parkinson disease: Notably, of these, six genes (LRRK2, PRKN, SNCA, PINK1, PARK7/DJ-1, and VPS35) have been unequivocally linked to monogenic PD.4 Variants in GBA1, although not monogenic, remain one of the most significant risk factors for PD.5 All seven genes are commonly included in PD diagnostic panels3,6.