SLC25A20 and hyperinsulinemic hypoglycemia, familial, 4: CACT deficiency is a rare autosomal recessive disorder caused by SLC25A20 deficiency (Indiveri et al., 2011), diagnosed as ACs (especially C16- and C18:1-AC) and reduced levels of free carnitine (Rubio-Gozalbo et al., 2004).