Genetic variant

rs9923231 a variant in the VKORC1 gene

rs9923231 is a single-letter difference in the VKORC1 gene, on chromosome 16. ClinVar, the public archive of variant interpretations, lists it as drug response: linked to how the body handles certain medicines. It has been reported in connection with Warfarin response and phenprocoumon response - Toxicity, among others. Carrying it does not, on its own, mean you have or will develop any condition.

ClinVar: Drug response
Drug Response
Chromosome 16

What is this?

Your DNA is a long sequence of four letters. At a few million positions, people commonly differ by a single letter; each of those positions is called a SNP (“snip”), and rs9923231 is the catalogue number of one of them, in the VKORC1 gene. Which letters you carry there — one copy from each parent — is your genotype.

VKORC1 (vitamin K epoxide reductase complex subunit 1): This gene encodes the catalytic subunit of the vitamin K epoxide reductase complex, which is responsible for the reduction of inactive vitamin K 2,3-epoxide to active vitamin K in the endoplasmic reticulum membrane. Vitamin K is a required co-factor for carboxylation of glutamic acid residues by vitamin K-dependent gamma-carboxylase in blood-clotting enzymes.
Gene description from NCBI Gene

Several SNPs in the VKORC1 gene have been linked to warfarin sensitivity, with perhaps the most comm...
From SNPedia

Why might it matter?

ClinVar records this variant as drug response, meaning linked to how the body handles certain medicines. A classification describes the variant, not you: what it means for one person depends on their genotype, their family history and often on other genes and circumstances.

Conditions it has been reported with

Warfarin response
phenprocoumon response - Toxicity
phenprocoumon response - Dosage
warfarin response - Toxicity
Venous thromboembolism
acenocoumarol response - Dosage
warfarin response - Efficacy
Thrombus
warfarin response - Dosage
VKORC1-related disorder

Listed in ClinVar submissions for this variant. Being listed is a report of an association, not a statement that the variant causes the condition in any given person.

Medicines

Warfarin dose adjustment strong

VKORC1 — affects warfarin sensitivity, key for dosing

Never start, stop or change a medicine because of a genetic result without speaking to the prescriber.

Do I have this variant?

If you have taken a consumer DNA test (23andMe, AncestryDNA and similar), you can download its raw data file and check. Create a free account, upload the file, and this page will show the letters you carry at rs9923231, if your test read this position.

Connect this with your blood results

A gene is a fixed instruction; a blood test shows what your body is doing now. CheckMyBloods reads the two side by side, so a variant can be set against the markers it could plausibly affect.

Blood markers related to VKORC1

VKORC1 variants affect warfarin dosing. If on blood thinners, share this with your doctor.

Blood markers do not diagnose a genetic condition, and a variant does not explain a blood result on its own. Together, with symptoms and family history, they give a clinician context.

Upload blood results

What should I do next?

Find out whether you carry it. Reading about a variant says nothing about you until you know your genotype.
Put it in context. Add your blood results, so the variant can be read against what your body is doing.
Ask questions. Dr. Hemsworth, our AI assistant, can explain this variant and your results in plain English.
Take anything that worries you to a professional. A GP or genetic counsellor can order a confirmatory test and interpret it with your history.

This page is general information drawn from public research databases. It cannot diagnose anything, and it is not a substitute for advice from a doctor or genetic counsellor who knows your history.

Technical details

dbSNP ID: rs9923231
Gene: VKORC1
Position (GRCh38): chr16:31096367
Variant type: snv
Consequence: intergenic variant
ClinVar classification: drug response