The most “popular” and well-documented are PFIC 1 (Byler disease or FIC1 deficiency), PFIC 2 (Byler syndrome or BSEP deficiency), and PFIC 3 (MDR3 deficiency) [1,8,9,11]. This evidence concerns the gene ATP8B1 and hyperinsulinemic hypoglycemia, familial, 4.