SLC2A2 and hyperinsulinemic hypoglycemia, familial, 4: In humans, mutations in the GLUT2-encoding gene SLC2A2 are associated with glycogen storage defects in kidneys and the liver, and a rare genetic SLC2A2 deficiency has been established as Fanconi–Bickel syndrome (FBS) which exhibits characteristic features such as hepatomegaly caused by glycogen accumulation, glucose and galactose intolerance, fasting hypoglycemia, tubular nephropathy, and disturbed growth [61, 144].