The Pharmacogene Variation (PharmVar) Consortium is the successor of the Human Cytochrome P450 (CYP) Allele Nomenclature website that served the pharmacogenetics community by designating CYP star (*) alleles. The aim of PharmVar is to continue the mission of serving as an official allele designation authority for the global pharmacogenetics community. Herein, we describe the introduction of the first non‐CYP gene to PharmVar. Pharmacogenetic variation of NUDT15 plays a significant role in thiopurine response variability and toxicity.