F11 and familial hypodysfibrinogenemia: Rare encountered CFDs, known as “rare” bleeding disorders (RBDs), comprise deficiency of fibrinogen, factor (F) II, FV, combined FV and FVIII, FVII, FX, FXI, FXIII, and vitamin K-dependent factors, which are transmitted autosomal recessive with the exception of some cases of FXI deficiency and dysfibrinogenemia that may be autosomal dominant.