SLC10A1 and hyperinsulinemic hypoglycemia, familial, 4: In fact, it has been noted that pruritus is a manifestation of cholestatic diseases, despite bile acid levels generally being only slightly above normal upper limits, and that in some diseases, such as sodium taurocholate cotransporting polypeptide (NTCP) deficiency, an inborn error of bile acid metabolism resulting in bile acid levels more than 80 times the normal, there is no pruritus [38,39,40,41,42].