Patients with CYP2C9*2 in combination with another normal function allele, a decreased function allele, or a no function allele may have increased risk of over-anticoagulation when treated with acenocoumarol as compared to patients with two normal function alleles. However, conflicting evidence has been reported. This drug-variant pair has been assigned a 鈥渘o recommendation鈥?by DPWG, as it was determined to be not clinically actionable.Other genetic and clinical factors may also influence the toxicity to acenocoumarol.