Leiden mutation is associated with?
**Core Concept**
The Leiden mutation refers to a specific genetic variation in the factor V gene, which codes for a protein involved in the coagulation cascade. This mutation leads to a change in the factor V protein, resulting in a hypercoagulable state.
**Why the Correct Answer is Right**
The Leiden mutation is a point mutation in the factor V gene, resulting in the substitution of arginine to glutamine at position 506 (R506Q). This mutation renders the factor V protein resistant to inactivation by activated protein C (APC), leading to an increased risk of thrombosis. The APC resistance is due to the impaired binding of APC to the factor V protein, which normally inactivates factor V. The Leiden mutation is a common cause of inherited thrombophilia.
**Why Each Wrong Option is Incorrect**
**Option A:** Factor VII deficiency is not associated with the Leiden mutation. Factor VII deficiency is a rare bleeding disorder caused by a deficiency of factor VII, which is not related to the factor V gene mutation.
**Option B:** Factor XIII deficiency is not associated with the Leiden mutation. Factor XIII deficiency is a rare bleeding disorder caused by a deficiency of factor XIII, which is not related to the factor V gene mutation.
**Option C:** Protein S deficiency is not associated with the Leiden mutation. Protein S deficiency is a rare bleeding disorder caused by a deficiency of protein S, which is not related to the factor V gene mutation.
**Clinical Pearl / High-Yield Fact**
The Leiden mutation is a common cause of inherited thrombophilia, and individuals with this mutation are at increased risk of developing venous thromboembolism, particularly deep vein thrombosis and pulmonary embolism. It is essential to consider the Leiden mutation in patients with a history of recurrent thrombosis or unexplained thrombosis.
**Correct Answer: D. Factor V Leiden mutation.**