Reducing GBA2 activity, genetically or by means of small compound inhibitors like the iminosugar AMP-DNM, has remarkable beneficial effects in Niemann Pick type C (NPC) mice with a defect in the lysosomal protein NPC1 mediating efflux of cholesterol from lysosomes and secondary GCase deficiency (Nietupski et al., 2012; Marques et al., 2015). Here, GBA2 is linked to hyperinsulinemic hypoglycemia, familial, 4.