Chitotriosidase, a chitinase secreted by activated macrophages (especially lipid-laden Gaucher cells), is markedly elevated in Gaucher disease and variably elevated in other lysosomal storage disorders, including but not limited to Niemann–Pick disease type A, B, and C (ASMD, NPC), MLD, Krabbe disease, galactosialidosis, and LALD. This evidence concerns the gene CHIT1 and Gaucher disease.