The lack of staining of neonatal Trpml3−/−; Trpml1−/− enterocytes (S3 Figure and Fig. 4E) with Periodic Acid Schiff, which labels glycosaminoglycans, with Toluidine Blue, which labels polysaccharides and nucleic acids, and with Oil Red O, which labels lipids, confirm that their pathological vacuoles do not densely accumulate these substances, which are found in the inclusion bodies of neurons from MLIV patients. The gene discussed is MCOLN3; the disease is mucolipidosis type IV.