Which hematologic disorder is most commonly associated with DVT and/or PE?

• A. Polycythemia Vera
• B. Protein C Deficiency
• C. Protein S Deficiency
• D. Factor V Leiden

Answer: (D)

Factor V Leiden is the most common inherited thrombophilia and is classically linked to venous thromboembolism, including DVT and PE. The mutation makes Factor V resistant to inactivation by activated protein C, so thrombin generation remains unchecked and clotting is promoted. This genetic alteration is particularly common in certain populations and explains why many cases of DVT/PE occur in individuals without other provoking factors.

Other listed conditions can predispose to DVT/PE as well, but they are less common causes overall. Polycythemia Vera can increase thrombosis risk due to high blood viscosity, and deficiencies of protein C or protein S reduce anticoagulant pathways, but Factor V Leiden remains the most frequent inherited trigger for these venous clots.