TPMT*3A Allele

**Semantic type:** Gene or Genome

**Definition:** Human TPMT*3A allele is located in the vicinity of 6p22.3 and is approximately 26 kb in length. This allele, a variant form of the TPMT wild-type allele, encodes thiopurine S-methyltransferase protein. TPMT*3A allele exhibits two clinically-relevant SNPs (c.615G>C and c.874A>G) in that results in coding changes (A154T and Y240C). Together, these alterations abolish the enzymatic activity of the protein encoded by this allelic variant.

**Synonyms:** - TPMT, A154T, Y240C - TPMT, c.615G>C, c.874A>G - TPMT-3A Allele