Sensitive

DPYD *2A — fluoropyrimidine tolerance

DPYD · rs3918290

Where this position leads

Drug: Fluoropyrimidines

rs3918290 Drug: Fluoropyrimidines Fluoropyrimidines Drug rs3918290 rs3918290 DPYD

What each result means

C/C No copy of DPYD*2A at this position.
C/T One copy of DPYD*2A, which destroys the splice site and leaves no enzyme from that copy. DPD clears about 80% of a dose of fluorouracil or capecitabine; with one working copy, clearance is roughly halved and CPIC recommends starting at a reduced dose with titration.
T/T Two copies of DPYD*2A — essentially no DPD activity. Standard fluoropyrimidine doses have caused fatal toxicity in this situation, and CPIC recommends avoiding these drugs. Extremely rare, and one of the strongest reasons pre-treatment DPYD testing exists at all.
This is a pharmacogenomic result with a published dosing guideline behind it. Tell a prescriber or pharmacist rather than acting on it — and never stop or change a prescribed medicine on the strength of a genotype.

Source: CPIC Guideline for Dihydropyrimidine Dehydrogenase Genotype and Fluoropyrimidine Dosing: 2017 Update, Clinical Pharmacology & Therapeutics (PMID 29152729).

Questions about rs3918290

What is rs3918290?

rs3918290 is a single position in the genome, in or near the DPYD gene. Published research associates it with dpyd *2a — fluoropyrimidine tolerance. A single variant does not decide an outcome — it shifts a probability, and for most common variants the shift is small.

Does rs3918290 affect how medicines work?

DPYD carries pharmacogenomic findings for Fluoropyrimidines. That is educational information, not a prescription or a dosing guide. Any decision to start, stop or change a medicine belongs with the clinician or pharmacist managing your treatment.

Does having rs3918290 mean I will get this?

No. Common variants like this one move a probability slightly and, on their own, rarely decide anything about one person. Nothing on this page is a diagnosis, and health decisions should be made with a clinician who can see your whole picture.

Where does the information about rs3918290 come from?

CPIC Guideline for Dihydropyrimidine Dehydrogenase Genotype and Fluoropyrimidine Dosing: 2017 Update, Clinical Pharmacology & Therapeutics (PMID 29152729). Every variant on MyGeneLog comes from public primary sources and is published with its citation and the date it was checked.

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