Wheeler, Caitlin AMasimirembwa, CMthembu, BBotha, JScholefield, JanineFabian, J2024-11-112024-11-112024-040256-95742078-5135https://doi.org/10.7196/SAMJ.2024.v114i3b.1367http://hdl.handle.net/10204/13804In the paediatric liver transplant programme in Johannesburg, South Africa (SA), tacrolimus is the calcineurin inhibitor of choice, comprising an essential component of the immunosuppression regimen. It is characterised by a narrow therapeutic index and wide interpatient variability, necessitating therapeutic drug monitoring of whole-blood concentrations. Pharmacogenetic research, although not representative of SA population groups, suggests that single-nucleotide polymorphisms within the cytochrome P450 3A5 (CYP3A5) gene contribute to the variability in tacrolimus dosing requirements. The rs776746 polymorphism, CYP3A5*3, results in a splice defect and a non-functional enzyme. Clinically, to reach the same tacrolimus concentration-to-dose ratio (CDR), expressors (CYP3A5*1/*1 and *1/*3) require a higher tacrolimus dose than non-expressors (*3/*3).FulltextenLiver transplantEnd-stage liver diseaseESLDTacrolimusCYP3A5PaediatricLiving DonorPharmacogeneticsPrecision medicineArticle28099