The deficiency of fibrinogen, prothrombin, factor V (FV), FVII, FVIII, FIX, FX, FXI, and FXIII, called rare coagulation disorders (RCDs), may result in coagulopathies leading to spontaneous or posttrauma and postsurgery hemorrhages.
In the present study, the gene encoding FXI (F11) was analyzed by direct sequencing in 33 individuals belonging to 11 unrelated Turkish families, and the bleeding tendency was quantitatively assessed by means of a bleeding questionnaire in 27 individuals with low FXI clotting activity and/or mutated F11 gene.
A new factor XI mutation (Gln 47 Pro) has been found in combination with another known mutation (Leu 619 Pro) in a female patient with FXI deficiency and a moderate bleeding tendency.
DNA analysis of patients reported eight novel mutations of the FXI gene but neither mutation location nor secretion or not of the variant correlated with the bleeding tendency.
Defects in platelets as well as inherited deficiencies of coagulation factors including fibrinogen, FII, FV, FV + FVIII, FVII, FX, FXI and FXIII deficiencies, generally lead to lifelong bleeding disorders, whose severity of bleeding symptoms is heterogeneous in platelets abnormalities but generally inversely proportional to the degree of the factor deficiency in rare bleeding disorders (RBDs).
Deficiencies of coagulation factors other than factor VIII and factor IX (afibrinogenemia, FII, FV, FV+FVIII, FVII, FX, FXI, FXIII) that cause bleeding disorders (RBDs) are inherited as autosomal recessive traits and are rare, with prevalences in the general population varying between 1 in 500,000 and 1 in 2 million for the homozygous forms.
The bleeding tendency associated with plasma FXI deficiency in patients is variable, with approximately 50% of patients exhibiting excessive post-traumatic or postsurgical bleeding.
An inhibitor of plasma thromboplastin antecedent (PTA, factor XI), measured in coagulant and radioimmunoassays, was detected in a 60-year-old man with carcinoma of the prostate who had no evidence of a bleeding tendency.