Congenital Factor V Deficiency

Peripartum anesthetic management of a parturient with inherited factor v deficiency

Inherited Factor V deficiency is a rare bleeding disorder. We describe the genetic analysis and anesthetic management of a parturient with severe Factor V deficiency who presented in spontaneous labor. Good hemostatic conditions were obtained with prophylactic fresh frozen plasma administration of 10 mL/kg. Detailed genetic analysis by next-generation sequencing identified several relevant mutations in the coding part of the Factor V (F5) gene in our patient, her parents, and the newborn.

Successful excision of a pseudotumour in a congenitally factor V deficient patient

We report a patient with congenital homozygous factor V deficiency in whom a large pseudotumour in the right upper leg was successfully surgically excised under continuous substitution with fresh-frozen plasma.

A description of two cases of factor V deficiency

We report two cases of factor V deficiency. A 12-year-old girl with thalassemia major was admitted for bone marrow transplant (mismatched). She was found to have a heterozygous deficiency of factor V (21%), but this was considered compatible with the transplant, which was performed without the support of suppernatant cryoprecipitate. A 14-year-old girl (factor V 2%) with a negative history (menarche at age 12, menstrual cycle regular and normal in quantity and length). One year previously she had complained of menorrhagia (length of period, 9 days); tests revealed server anaemia (Hb 4.9 g/dl). We show how even severe cases of factor V deficiency may often be silent, and not require transfusion in surgical procedures, thus avoiding the risks associated with such therapy.

Abnormal formation of the prothrombinase complex: factor V deficiency and related disorders

A membrane-bound, Ca2-dependent complex of the cofactor factor Va and the enzyme factor Xa comprises the prothrombinase coagulation complex, which catalyzes the proteolytic conversion of prothrombin to thrombin. In normal hemostasis, the platelet is presumed to supply the surface membrane and thus constitutes the site at which an enzymatically functional complex assembles and thrombin generation occurs. Factor Va, the two subunit protein produced by thrombin activation of factor V, is an essential, nonenzymatic cofactor of the prothrombinase complex. Factor Va performs its cofactor role in part by binding to the platelet membrane and functioning as the membrane receptor for factor Xa in a 1:1 stoichiometric complex of high affinity (Kd = 10(-10) M). Factor Va also appears to participate in the binding of prothrombin to the enzymatic complex. Because deletion of factor Va from the prothrombinase complex decreases the rate of thrombin generation by four orders of magnitude, the essential role it plays is easily understood. Therefore, in the evaluation of factor Va function in the prothrombinase complex, the ability of factor Va to support various binding interactions with the platelet, factor Xa, and prothrombin must be considered. Factor Va can be made available from two potential blood compartments: the plasma and platelets. Approximately 80 per cent of the total blood factor V circulates in plasma whereas the remaining 20 per cent is contained within platelet granules. The relative contribution of plasma versus platelet factor V to factor Va binding interactions in the prothrombinase complex are not clearly defined. However, data from our laboratory and several others suggest that factor V stored and released from platelets is of utmost importance in maintaining normal hemostasis. A discussion of these data relative to congenital and acquired deficiencies of both plasma and platelet factor V is the subject of this report.