Genes involved: CYP4F2, CYP2C9, VKORC1, GGCX rs11676382

54-year-old male needs to be started on Coumadin (warfarin) for a newly identified deep vein thrombosis (DVT).

Genetic findings:

• VKORC1 1639/3673 AA (warfarin sensitive)
• CYP4F2 V433M TT (homozygous mutant)
• GGCX rs11676382 GG (homozygous mutant)
• CYP2C9*2 CC (wildtype)
• CYP2C9*3 AA (wildtype)
• CYP2C9*5 CC (wildtype)
• CYP2C9*6 A- (heterozygous)

Using an evidence-based online tool *11 which accounts for various patient characteristics, disease conditions, concurrent medications, and genetic findings, we can estimate the patient’s required mini-loading dose to be 3.5mg for the initial dose, and the estimated therapeutic daily dose thereafter is 2.4mg daily. This is to achieve an INR goal of 2.5 (2-3 goal range.)

Outcome:

Personalised warfarin dosing schemes with a goal of improving time in therapeutic range and reducing the incidence of bleeding events.