F5 and hemorrhagic disease: Rare bleeding disorders (RBDs) are a group of diseases that are caused by a genetic mutation in one or more clotting factors, such as factor VII (FVII), factor X (FX), factor XI (FXI), factor XIII (FXIII), factor I (FI), factor II (FII), factor V (FV), combined FV and factor VIII (FVIII), and vitamin K-dependent clotting factors.