LRRK2 and Parkinson disease: We observed a significant increase in the total GlcCer/total Cer ratio from 1.9 ± 0.5 (mean ± SD) in PD subjects without LRRK2 variants to 2.2 ± 0.6 (mean ± SD) in PD subjects with a LRRK2 variant (unadjusted p = 0.02) (Fig. 7C), suggesting GlcCer catabolism is reduced in LRRK2-PD patients.