CPT2 and hyperinsulinemic hypoglycemia, familial, 4: In conjunction with lowered concentrations of glucose and unchanged ketogenesis (Figure 2—figure supplement 1C), this constellation is a metabolic ‘signature’ of a frequent inherited human disorder characterized by inefficient β-oxidation of fatty acids due to mitochondrial carnitine palmitoyltransferase II deficiency (Gempel et al., 2002; Bonnefont et al., 2004).