Indeed, amelioration by metformin of PPHN23–25 and pulmonary hypertension in the adult5,27,91,92 has been noted26, which may be mediated, at least in part, through AMPK activation as opposed to reduced efficiency of redox and electron transfer at mitochondrial complex I per se30 or inhibition of fructose-1,6 bisphosphatase31. This evidence concerns the gene PRKAA2 and pulmonary hypertension.