The FAH−/− offspring showed severe liver damage, but unlike humans, FAH‐deficiency in pigs causes a lethal defect in utero, and interestingly the defect of FAH could be cured by 2‐(2‐nitro‐4‐trifluoromethylbenzoyl)‐1,3 cyclohexanedione (NTBC). Here, FAH is linked to hyperinsulinemic hypoglycemia, familial, 4.