The main function of this Web page is to encourage scientists worldwide to speak the same language and to avoid "home-made" allelic designations that can confuse the nomenclature system and the scientific literature.

It contains the recommended nomenclature for the human polymorphic TPMT gene. It adheres to the guidelines provided in Antonarakis and the Nomenclature Working Group (1998) and den Dunnen and Antonarakis (2001) as detailed below:

  1. On this website only human TPMT alleles are considered. 
  2. The gene and allele is separated by an asterisk followed by Arabic numerals (e.g. TPMT*1, TPMT*3A). 
  3. To be assigned as a unique allele it should contain nucleotide changes that have been shown to affect transcription, splicing, translation, posttranscriptional or posttranslational modifications or result in at least one amino acid change. 
  4. Additional nucleotide changes and combinations of nucleotide changes, including silent mutations in the gene will be given letters (e.g. *1A, *1S).
  5. Numbering of nucleotides in the allele should be as described in Antonarakis and the Nomenclature Working Group (1998). The base A in the initiation codon ATG is denoted +1 and the base before A is numbered -1. 
  6. Submission of new alleles should be done with information sufficient to fulfil the criteria to be assigned a unique allele as under # 4 above or a letter as described under # 5 above. For incorporation into the Web page as a unique allele, all exons and exon-intron borders should have been sequenced. If a new allele has been detected on the cDNA level, verification of the mutation(s) on the genomic level is required. For acceptance of a new SNP given a separate letter, evidence for its presence on the genomic level is required. 
  7. No temporary allelic numbers or letters are provided, and information about any new allele submitted, will continuously be published on the web Page. In case an author does not want to release the information on the web page before publication, the Webmaster can usually provide him or her with an allelic designation but not release the information on the web page until the manuscript has been accepted or published.
  8. The new allele should after designation be submitted to dbSNP (NCBI).