Na+-Taurocholate Cotransporting polypeptide deficiency (NTCPD) is an autosomal recessive disorder affecting the hepatic uptake of bile acids caused by biallelic variants of the solute carrier family 10 member1 (SLC10A1) gene which encodes NTCP protein. This evidence concerns the gene SLC10A1 and hyperinsulinemic hypoglycemia, familial, 4.