SLC35A2 and Hyperbilirubinemia: This is done by conjugating bilirubin with glucuronic acid by bilirubin uridine diphosphate-glucuronosyltransferase (UGT), a microsomal enzyme [13].Unconjugated hyperbilirubinemia can be caused by either decreased uptake of bilirubin by liver cells or a defect in conjugation.