This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Warfarin sensitivity is a condition that is characterized by a reduced tolerance for a “blood-thinning” medication called warfarin. Warfarin is an anticoagulant that is often prescribed to people who are at an increased risk for blood clots. People with a warfarin sensitivity respond more strongly to lower doses of warfarin and are, therefore, more likely to experience an overdose or other serious side effects from the medication. They may experience abnormal bleeding in the brain, gastrointestinal tract, or other tissues even at average doses. The metabolism of warfarin and the drug’s effects in the body are complex traits that are determined by several genes as well as environmental and lifestyle factors such as gender, age, weight, diet, and other medications. Two specific genetic polymorphisms in the CYP2C9 and VKORC1 genes account for approximately 30-40% of variation in the response to warfarin and can be passed on to future generations in an autosomal dominant manner.
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