biostudies-literatureRodriguez-Antona COntario Institute for Cancer ResearchKungliga Tekniska HögskolanVetenskapsrådetErzincan ÜniversitesiRobert Bosch StiftungNHGRI NIH HHSMcGill UniversityNational Institutes of HealthNational Human Genome Research InstituteNIGMS NIH HHS1159-1171https://www.ebi.ac.uk/biostudies/studies/S-EPMC9399309biostudies-literatureUnknown112(6)The Pharmacogene Variation Consortium (PharmVar) catalogs star (*) allele nomenclature for the polymorphic human CYP3A5 gene. Genetic variation within the CYP3A5 gene locus impacts the metabolism of several clinically important drugs, including the immunosuppressants tacrolimus, sirolimus, cyclosporine, and the benzodiazepine midazolam. Variable CYP3A5 activity is of clinical importance regarding tacrolimus metabolism. This GeneFocus provides a CYP3A5 gene summary with a focus on aspects regarding standardized nomenclature. In addition, this review also summarizes recent changes and updates, including the retirement of several allelic variants and provides an overview of how PharmVar CYP3A5 star allele nomenclature is utilized by the Pharmacogenomics Knowledgebase (PharmGKB) and the ClinicClinical pharmacology and therapeuticsPharmVar GeneFocus: CYP3A5.PMC93993092016‐011548755102016‐01153U24 HG010615R35 GM140845U01 HG0102452019‐01837Boone ECWhirl-Carrillo MGilep AAKlein TERodriguez-Antona CDrogemoller BISavieo JLWang Dvan Schaik RHNPeter APGaedigk ARamey BESangkuhl KPratt VMLauschke VMfalsePharmVar GeneFocus: CYP3A5.The Pharmacogene Variation Consortium (PharmVar) catalogs star (*) allele nomenclature for the polymorphic human CYP3A5 gene. Genetic variation within the CYP3A5 gene locus impacts the metabolism of several clinically important drugs, including the immunosuppressants tacrolimus, sirolimus, cyclosporine, and the benzodiazepine midazolam. Variable CYP3A5 activity is of clinical importance regarding tacrolimus metabolism. This GeneFocus provides a CYP3A5 gene summary with a focus on aspects regarding standardized nomenclature. In addition, this review also summarizes recent changes and updates, including the retirement of several allelic variants and provides an overview of how PharmVar CYP3A5 star allele nomenclature is utilized by the Pharmacogenomics Knowledgebase (PharmGKB) and the Clinic2022-01-01T00:00:00Z2022 Dec2025-05-29T21:47:07.797Z2025-02-19T01:16:58.323ZS-EPMC93993093520248410.1002/cpt.2563