APC and Rare hereditary thrombophilia: At the same time, in case of its homologous factor V, APC resistance (factor V Leiden, Arg506Gln) conveys a risk of venous thromboembolism that is increased by 50–100-fold and 5–10-fold in homozygous and heterozygous patients, respectively, and mutation in this factor is known to be associated with the most prevalent inherited thrombophilia [17].