MCOLN1 and lysosomal storage disease: It is well known that mutations in the MCOLN1 gene in humans cause ML-IV disorder, a neurodegenerative and lysosomal storage disorder with various neuronal symptoms, including psychomotor retardation and vision impairment (Bargal et al., 2000, Bassi et al., 2000, Wakabayashi et al., 2011).