Consistent with the hypothesis that growth failure in LPI may be driven by cationic amino acid deficiency and subsequent perturbations in the GH/IGF-1 axis, the Slc7a7Lbu/Lbu knockout mouse model exhibits the classical biochemical phenotype (low plasma concentrations and increased urinary excretion of the cationic amino acids) and reduced hepatic expression of Igf1 during the postnatal period (Stroup et al., 2020). This evidence concerns the gene IGF1 and hyperinsulinemic hypoglycemia, familial, 4.