Factor V Leiden is a genetic mutation that affects the blood's ability to clot. It leads to an increased risk of developing abnormal blood clots, particularly in the veins, a condition known as venous thromboembolism. This mutation occurs in the factor V gene, which plays a crucial role in the coagulation process. People with Factor V Leiden may not show symptoms until they experience a clotting event. Diagnosis typically involves blood tests to identify the mutation. Management often includes blood thinners to reduce the risk of clots, especially during high-risk situations like surgery or prolonged immobility.