MCOLN1 and mucolipidosis type IV: Furthermore, CCCP and H2O2 treatment failed to increase LC3-II levels in mucolipidosis IV patient-derived TRPML1 KO (ML-IV) fibroblasts (Fig. 3d,e and Supplementary Fig. 18), which exhibited high basal levels of LC3-II compared with WT cells (Supplementary Fig. 19).