The enzyme VKORC1 (full name: Vitamin K epoxide reductase complex 1) is involved in the activation of vitamin K, a vitamin that in turn plays a role in blood clotting. If you have a deficiency of vitamin K, some clotting processes are unable to take place, as a result of which haemorrhages can occur. Controlled use is made of this mechanism to prevent thrombosis: inhibiting the enzyme VKORC1, with the help of blood thinners, results in clots developing in the blood vessels less quickly.
Anticoagulants (blood thinners) that are known to reduce vitamin K production are the coumarins acenocoumarol, phenprocoumon and warfarin. If you have a reduced level of the enzyme VKORC1, these drugs may have a different effect than expected and may be easily overdosed.
Acenocoumarol and the enzyme VKORC1
Acenocoumarol is processed within the body primarily by the enzyme VKORC1. The activity of this enzyme can vary considerably depending on your genetic predisposition, which means the efficacy of acenocoumarol can also differ from person to person.
Information about your genetic predisposition may therefore provide grounds for extra vigilance in relation to the effectiveness of the treatment, for adjustment of the dose or for more frequent checks by the thrombosis clinic.
Read more about Acenocoumarol »
Phenprocoumon and the enzyme VKORC1
Phenprocoumon is processed within the body primarily by the enzyme VKORC1. The activity of this enzyme can vary considerably depending on your genetic predisposition, which means the efficacy of phenprocoumon can also differ from person to person.
Information about your genetic predisposition may therefore provide grounds for extra vigilance in relation to the effectiveness of the treatment, for adjustment of the dose or for more frequent checks by the thrombosis clinic.
Read more about Phenprocoumon »
Genetic predisposition
The activity of the enzyme VKORC1 varies from one individual to another.
This variation can be partly explained by genetic variations. Around 15% of people with a European background have significantly reduced activity of the enzyme VKORC1 and, consequently, increased sensitivity to coumarins.
The percentage is much higher in the case of people of East Asian origin.
As anticoagulants need to be dosed precisely, it may be important to know what VKORC1 genotype you have.
When a genotype is determined these variations in the VKORC1 gene are indicated by the nucleotide number followed by the nucleotide change. An example of a possible VKORC1 genotype is 1173CT.
At iGene we determine the following variants (alleles) of the VKORC1 gene: 1173C>T (is linked to variant -1639G>A).