starAllele — HL7 International OID Registry
The star allele nomenclature is commonly used in pharmacogenomics as shorthand to specify one or more specific variants in a gene that is known to impact drug metabolism or response. A star allele can identify either a single variant or a group of variants found in cis, and therefore it usually represents a haplotype. A star allele name is composed of the gene symbol and an allele number, separated by an asterisk, e.g. TPMT*2. By convention, the *1 allele represents the allele that contains the "reference" sequence, although that is not true in all cases. Closely related alleles may be assigned a common number and be differentiated by a unique letter that specifies the suballele (e.g., TPMT*3A, TPMT*3B). Pharmacogenomics tests commonly report patient phenotypes as diplotypes, i.e. *1/*3A.