Question

Which of the following clotting factor in a patient on Warfarin therapy, would have decreased gamma carboxyglutamate residue?

• A. Factor 2
• B. Factor 11
• C. Tissue factor
• D. Factor 5

Answer 1

The Correct Option is A

To understand which clotting factor would have decreased gamma carboxyglutamate residues in a patient on Warfarin therapy, we must first comprehend the impact of Warfarin. Warfarin, a commonly used anticoagulant, acts by inhibiting the enzyme vitamin K epoxide reductase. This enzyme is essential for the reduction of vitamin K, which is a crucial cofactor in the synthesis of gamma carboxyglutamate residues in several clotting factors.

Clotting factors that depend on vitamin K for their gamma carboxylation include Factor II (Prothrombin), Factor VII, Factor IX, and Factor X. These gamma carboxyglutamate residues are necessary for calcium binding, which in turn is vital for the proper functioning of these factors in the coagulation cascade.

In patients on Warfarin therapy, the inhibition of vitamin K recycling leads to reduced gamma carboxylation of these vitamin K-dependent factors, thus impairing their function. Out of the options provided:

• Factor 2 (Prothrombin): This is vitamin K-dependent and would indeed have decreased gamma carboxyglutamate residues.
• Factor 11: This factor is not vitamin K-dependent and would remain largely unaffected in terms of gamma carboxylation.
• Tissue factor: This is not directly affected by Warfarin, as it does not rely on vitamin K for its gamma carboxylation.
• Factor 5: Like Factor 11, this factor is not vitamin K-dependent and does not rely on gamma carboxylation.

Based on this analysis, the correct answer is Factor 2, as it is a vitamin K-dependent clotting factor, and its gamma carboxyglutamate residues would be decreased due to the effect of Warfarin.