|| incapable of detoxifying certain drugs
|| detoxifying ability of certain drugs may be diminished
|| normal for 23andMe
, also known as A80P, is a rare 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 (in orientation to the dbSNP entry) is rs1800462(C), and it encodes the TPMT*2 allele. It may occur at a frequency of 1 in 200 alleles among Caucasians.
[wikipedia] thiopurine drugs metabolized by TPMT include azathioprine, mercaptopurine, and thioguanine
[PMID 23133420] Pharmacogenomic Diversity among Brazilians: Influence of Ancestry, Self-Reported Color, and Geographical Origin.
[PMID 22385887] High prevalence of polymorphism and low activity of thiopurine methyltransferase in patients with inflammatory bowel disease.
[PMID 18685564] Genetic polymorphism of inosine triphosphate pyrophosphatase is a determinant of mercaptopurine metabolism and toxicity during treatment for acute lymphoblastic leukemia.
[PMID 18547414] Genotyping panel for assessing response to cancer chemotherapy.