Pyridoxine-dependent epilepsy due to ALDH7A1 deficiency (PDE-ALDH7A1) is a rare but treatable epileptic encephalopathy caused by disruption of lysine catabolism and secondary depletion of pyridoxal-5'-phosphate (PLP). This evidence concerns the gene ALDH7A1 and hyperinsulinemic hypoglycemia, familial, 4.