SLC35A2 and Gilbert syndrome: Regarding the pharmacogenetics of Gilbert’s syndrome and drug side effects, there are two examples with mechanisms that are likely to influence the future administration of drugs, and potentially the drug-licensing process as well: irinotecan, the SN-38 metabolite of which is a UGT substrate, and ATV, which is not a substrate for glucuronidation, but nevertheless conveys a significant risk of unwanted jaundice by means of UGT inhibition [18].