Rs1142345

rs1142345 is a SNP in the TPMT gene, potentially encoding a variant incapable of detoxifying byproducts of certain antineoplastic and immunosuppressant drugs. In general, individuals must have two nonfunctioning TPMT alleles for the toxicity to be pronounced.

The risk allele for this SNP is rs1142345(G), and when it is the only variant in the TPMT gene, it encodes the TPMT*3C allele. While still rare, it is more common in African-Americans (2.4% of all alleles) than in Caucasians. Note that if the same allele also carries the rs1800460(A) SNP, the allele is actually a TPMT*3A allele (OMIM).

The medicine 6-Mercaptopurine is metabolized by TPMT. Individual differences in TPMT activity associated with this SNP are now used to determine appropriate dosage range and interval for treatment.

23andMe blog hearing loss linked to a chemotherapy drug named Cisplatin.

[| wikipedia] thiopurine drugs metabolized by TPMT include azathioprine, mercaptopurine, and thioguanine