Mammals have three mucolipin paralogs, encoded by the genes Trpml1, 2 and 3. Mutations in human Trpml1 (also known as Mcoln1) cause mucolipidosis type IV, a lysosomal storage disorder characterized by severe psychomotor retardation and ophthalmological abnormalities that typically appear months after birth but within the first year of life [10], [11]. This evidence concerns the gene MCOLN1 and mucolipidosis type IV.