LRRK2 and Parkinson disease: In fact, it has been reported that the ratio of pS935-LRRK2 to total LRRK2 is significantly reduced in human PBMC lysates from PD manifesting LRRK2 G2019S carriers compared to iPD samples and healthy controls [with and without G2019S mutations (Padmanabhan et al., 2020)], although an alternative in-house developed ELISA detected a slight but significant increase in pS935-LRRK2 in PBMCs of iPD, compared to healthy controls (Melachroinou et al., 2020).