Given the complex clinical presentation of MLIV, including retinal degeneration, optic nerve pathology, and malfunctioning of parietal cells in the stomach leading to achlorhydria, a therapeutic approach involving systemic administration of CPP16-MCOLN1 that simultaneously targets the CNS, the eye, and peripheral organs may help to elicit maximal benefits in MLIV in the clinical setting. This evidence concerns the gene MCOLN1 and mucolipidosis type IV.