rs1800460
A SNP in the TPMT gene on chromosome 6. Its most notable genotype is T;T: incapable of detoxifying byproducts of certain drugs
- Gene
- TPMT
- Location
- Chr 618,138,997 (GRCh38)
- Highest magnitude
- 3.5Important
- Tested on
- 23andMe, AncestryDNA, FamilyTreeDNA
- Minor allele frequency
- 2%
Genotypes
Plus strand, as in 23andMe and AncestryDNA files.
- T;TMost notableBadincapable of detoxifying byproducts of certain drugs
- C;TBad(TPMT*3B) impaired drug metabolism
- C;CGoodnormal
SNPedia records rs1800460 on the minus strand: (A;A), (A;G), (G;G). Magnitude rates how notable a genotype is from 0 to 10, not how risky it is.
Related
Conditions, medicines and genes
Other TPMT SNPs
- rs1142345C;Cpossibly incapable of detoxifying certain drugsImportant
- rs1800462G;Gincapable of detoxifying certain drugsImportant
- rs1800584T;TTPMT*4A homozygote; likely issues detoxifying certain drugsImportant
- rs56161402T;TTPMT*8 homozygote; likely issues detoxifying certain drugsWorth knowing
- rs2842951C;Ccommon in complete genomicsTypical
Notes
From SNPedia
Show notes, about 180 words
rs1800460 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 rs1800460(A), and when it is the only variation in the TPMT gene, it encodes the TPMT*3B allele. While still rare, it is more common in Caucasians (4.5% of all alleles) than in African-Americans (0.8%). Note that if the same allele also carries the rs1142345(G) 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. http://en.wikipedia.org/wiki/Thiopurine_methyltransferase Wikipedia thiopurine drugs metabolized by TPMT include azathioprine, mercaptopurine, and thioguanine
T;T
http://blog.23andme.com/health-traits/do-you-know-how-youll-respond-to-thiopurine-medications/
Source and license
Adapted from rs1800460 on SNPedia, using a snapshot taken October 16, 2026. SNPedia content is shared under CC BY-NC-SA 3.0 US, and this page is shared under the same license.
SNPedia is a community-edited wiki. Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice. Magnitude is a community rating of how interesting a genotype is, not a risk score.