Although the function of GPNMB in modifying NCL pathology has not been investigated in a clinical or pre-clinical settings, it has been shown that GPNMB is elevated in Niemann–Pick disease type C1 (NPC1) mice and patients, a rare and fatal neurodegenerative–LSD that arises from lysosomal accumulation of unesterified cholesterol and glycosphingolipids [130] and may be a potential biomarker for therapeutic trials [163]. This evidence concerns the gene GPNMB and Niemann-Pick disease, type C1.