The variants included in the alleles are based on the PharmVar core alleles (for core allele definitions only, see https://www.pharmvar.org/gene/NUDT15). In addition, variants that present in the core allele for one star allele but also present in some but not all suballeles of another star allele are included in the other star allele as ambiguous changes, e.g. the *3 consensus allele includes a "GAGTCG(3) or GAGTCG(4)" at the position 55_56insGAGTCG since this variant defines the *6 core allele but is not part of the *3 core allele definition in PharmVar since it is not present in all *3 suballeles. These postions are represented in grey (G) in the Comparative Allele ViewEr (CAVE) tool at PharmVar.