Notably, mice that are deficient in enzymes that we found to be downregulated in the Mwk cerebellum also display cerebellar dysfunction including Scp2 knockout mice (42), Smpd1-deficient mice, a model of Niemann-Pick disease (43), and Gm2a knockout mice, a model of GM2-gangliosidosis (44). This evidence concerns the gene GM2A and Niemann-Pick disease.