rs1800462 TPMT
Normal TPMT function at *2 position.
What is rs1800462?
rs1800462 is a single-nucleotide polymorphism (SNP) in the TPMT gene (Thiopurine S-methyltransferase). Each person carries two copies, one from each parent, so a result is reported as a pair of letters such as CC. The table below describes what studies associate with each genotype; the association is statistical, across populations, and is not a diagnosis.
What does each rs1800462 genotype mean?
| Genotype | Association | What the evidence says | Confidence |
|---|---|---|---|
| CC | typical | Normal TPMT function at *2 position. | 90% |
| CG | increased | TPMT *2 carrier. No enzyme function from this allele. Reduced thiopurine dose recommended. | 90% |
| GG | increased | TPMT *2 homozygous. No enzyme function. Avoid thiopurines or use 10% dose. | 90% |
Is rs1800462 on 23andMe and AncestryDNA chips?
Yes — it is genotyped directly on 23andMe V3, 23andMe V4, 23andMe V5. Orviva reads it from a raw-data export without imputation.
Sources
Upload your 23andMe, AncestryDNA or WeGene raw file → · Ask G2: “What is my genotype at rs1800462 and what does it mean for me?”
Genetic associations describe risk across populations, not a diagnosis for any one person. Most variants shift risk modestly and act alongside lifestyle, environment and other genes. Consumer DNA chips do not read every position and can be wrong at any single one. For general education only; talk to a clinician or genetic counsellor before acting on anything here, and never change a prescribed medicine without your prescriber.