[A family of congenital combined deficiency of factor V and von Willebrand factor]

A family with inherited combined deficiency of factor V and von Willebrand factor (vWF) is reported. Hematological examination of 41 year-old female proband and her younger brother revealed prolonged prothrombin time and Kaolin partial thromboplastin time. The level of both factor V activity and factor V antigen markedly decreased, below 15% of normal. The decreased levels of factor VIII activity and vWF activity are also seen. Furthermore, abnormal mobilities were observed in crossed immunoelectrophoresis. The protein C, S antigens and activities, and protein C inhibitor activity were within normal. Four sons have received the 50% levels of factor V from their parents. One of them also showed the 50% of factor VIII and vWF activities. From above results, this family is thought to be a case of inherited deficiency of factor V and vWF, which are transmitted as an autosomal trait apparently.

Hereditary combined deficiency of clotting factors V and VIII with involvement of von Willebrand factor

A family is described in which two brothers, with a significant haemorrhagic disorder, are affected by combined factor V/VIII deficiency. In one of these patients an abnormal decrease of von Willebrand factor was also observed. Family studies suggest that both of the brothers are homozygous for a recessive gene. Normal laboratory results were found in eight other family members although seven of them had reported a mild bleeding tendency. The results indicate that hereditary combined factor V/VIII deficiency is a heterogeneous disorder and that defects of von Willebrand factor might be involved in the aetiology of the disease in some families.

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.

Combined factor V/VIII deficiency: a case report including levels of factor V and factor VIII coagulant and antigen as well as protein C inhibitor

Comprehensive coagulation studies were performed on members of a family with combined factor V/VIII deficiency. The purpose of these studies was to investigate the hypothesis that combined factor V/VIII deficiency is due to a lack of the inhibitor to activated protein C. The analyses performed included routine APTT and PT, factor V and VIII coagulant activity and antigen levels, von Willebrand factor levels, protein C antigen assay, and both protein C inhibitor activity and antigen levels. Three of the 19 family members studied were found to have a deficiency of both factors V and VIII. These three individuals showed prolonged APTTs and PTs and decreased levels of factor V and factor VIII coagulant activity and antigen. Factor VIII related antigen and ristocetin cofactor (von Willebrand factor) levels were normal. Protein C and both protein C inhibitor activity and antigen levels were also found to be normal. These findings confirm the results of other recent investigators and indicate that the autosomal, inherited combined factor V/VIII deficiency is not due to a protein C inhibitor deficiency. The real defect in this combined deficiency remains to be determined.

Combined factor V and factor VIII deficiency with normal protein C and protein C inhibitor. A family study

Combined deficiency of factor V and factor VIII, a rare bleeding disorder, is reported in a Syrian family. 2 siblings, 10 and 6 yr old are affected. They had mild bleeding manifestations. Their prothrombin time and partial thromboplastin time were prolonged, but thrombin time was normal. Both had low levels of factor V, (6% and 7%), factor VIII, (both 10%) factor VCAg (both 6%) and factor VIII CAg, (6% and 4%). All members of this family had normal levels of factor VIIIR:Ag, protein C, antigen and protein C inhibitor. The normal levels of protein C and protein C inhibitor in the 2 affected family members indicate that the combined deficiency of factors V and VIII has nothing to do with protein C. This contrasts with previous reports that deficiency of protein C inhibitor is the cause of combined factor V and factor VIII deficiency. The probable mode of inheritance of this defect is discussed.

Factor V (Quebec): a bleeding diathesis associated with a qualitative platelet Factor V deficiency

Studies were performed on a French-Canadian family afflicted with a bleeding disorder exhibiting an autosomal dominant inheritance pattern and a severe bleeding diathesis after trauma. Clinical laboratory coagulation tests were unimpressive; the only persistent abnormalities include mild thrombocytopenia and moderately reduced Factor V clotting activities. Some individuals had prolonged Stypven times when platelet-rich plasma was used, suggesting that their platelets could not support functional prothrombinase complex assembly. Detailed studies were performed by use of plasma and isolated, washed platelets from a sister and brother. Bioassay data indicate that both individuals had Factor V activities of approximately 40 and 36% of normal, respectively. A comparison of the Factor V radioimmunoassay and bioassay data on the brother's plasma indicated that the circulating amount of Factor V functional activity was low relative to Factor V antigen concentration (approximately 65-75%). In both individuals, the platelet Factor V functional activities were extremely low (2-4%) relative to antigen levels present as determined by radioimmunoassay. These discrepancies between Factor V activities and antigen concentration do not appear to be due to an unstable Factor V molecule or to the presence of a Factor V or Factor Va inhibitor or inactivator. Kinetics of prothrombin activation by use of purified clotting factors indicated that thrombin-activated platelets from both individuals supported prothrombinase complex assembly identical to controls in the presence of added purified Factor Va. Consequently, their bleeding diathesis appears to reflect their platelet, rather than their plasma, Factor V activity. These results suggest that platelet Factor V is an essential component in maintaining stable and prolonged hemostasis after trauma.

Inherited factor V deficiency. Study of a Brazilian family

Isolated Factor V deficiency is a very rare inherited coagulopathy. A genealogy of Brazilian Caucasians, where this disorder occurs, is reported. In this family, which was located because 2 affected individuals having the same surname were found by chance, the genealogical and laboratory data suggest an autosomal recessive pattern of inheritance. Nevertheless, the existence of deceased individuals who were reported as symptomatic seems to imply that some heterozygotes may present occasional bleeding episodes.

Normal titer of functional and immunoreactive protein-C inhibitor in plasma of patients with congenital combined deficiency of factor V and factor VIII

Protein-C inhibitor (PCI) is a newly described plasma inhibitor directed against a vitamin-K-dependent serine protease, activated protein-C, which is involved in the inactivation of factor V and factor VIII. Marlar and Griffin have reported that PCI activity is absent in the plasma of patients with congenital combined factor V/VIII deficiency. We have measured the levels of PCI in the plasma of seven unrelated patients with this disorder using both functional and immunologic methods. The rate at which the amidolytic activity of activated protein-C was neutralized in the patients' plasma was essentially identical to that observed in normal plasma. The titer of PCI antigen, as measured by an electroimmunoassay using a monospecific anti-PCI serum, was 5.3 +/- 1.6 micrograms/ml in the patients' plasma and was not significantly different from that of normal plasma (5.3 +/- 2.7 micrograms/ml, n = 30). The levels of factor-V-related antigen, factor V coagulant antigen, and factor VIII coagulant antigen were low in all patient plasma and were in good agreement with their respective coagulant activity. Our results do not appear to support the hypothesis that combined factor V/VIII defect is due to a lack of PCI.

Heterogeneity of human factor V deficiency. Evidence for the existence of antigen-positive variants

Functional human Factor V has been purified using a rapid immunoaffinity method. Following barium citrate adsorption of plasma, Factor V was precipitated with polyethylene glycol at a concentration between 5 and 14%. The resulting preparation was applied to a column containing an immobilized immunoadsorbent consisting of an IgG fraction containing a naturally occurring human monoclonal (IgG(4)lambda) antibody with inhibitory activity against human Factor V. The solid phase immunoglobulin quantitatively bound Factor V from human plasma. The bound Factor V was effectively eluted with a Tris buffer pH 7.2 containing 1.2 M NaCl and 1 M alpha-methyl-D-mannoside. The isolated native Factor V with high specific activity (92 U/mg) showed a single band (M(r), 350,000) on both reduced and nonreduced sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Factor V was purified 5,100-fold over plasma with an overall yield of 77%. The purified Factor V when subjected to thrombin activation exhibited an 18-fold increase in coagulant activity. The isolated Factor V neutralized the inhibitory activities of the monoclonal antibody that was used to purify it, as well as the rabbit antibodies produced by immunizing the animals with the purified Factor V. Immunoelectrophoresis of purified Factor V against the polyclonal rabbit antiserum resulted in a single precipitin arc of identical mobility to the Factor V in normal human plasma. Analysis by double immunodiffusion showed a line of identity between plasma and purified Factor V and crossed immunoelectrophoresis showed a single species in normal plasma.A competitive enzyme-linked immunosorbent assay using the rabbit antibody against Factor V was applied to quantify Factor V antigen level in human plasma. Reconstitution of congenitally deficient or immunodepleted plasma with normal plasma or purified Factor V gave parallel dose-response curves. In 14 normal plasma the coagulant activity was 0.98+/-0.02 U/ml (mean+/-SEM) and antigen concentration was 11.1+/-0.4 mug/ml. A pool of 14 patients with congenital Factor V deficiency were studied. 10 patients had Factor V antigen ranging from 1.0 to 2.4 mug/ml with corresponding coagulant activities (0-0.17 U/ml) indicating a low concentration of normal Factor V, presumably due to decreased synthesis or increased degradation. When these patient plasmas and the normal plasmas were analyzed together an excellent correlation (r = 0.97, P < 0.01) was obtained. However, four patients with coagulant activity (0-0.08 U/ml) had Factor V antigen concentrations ranging from 4.4 to 6.1 mug/ml, indicating the presence of a reduced concentration of abnormal Factor V protein. The presence of patients with antigen similar in concentration to coagulant activity and antigen in excess of Factor V activity indicates the heterogeneity of congenital Factor V deficiency.

Combined factor V and factor VII deficiency. Report of a case with a record on combined defects and considerations on the relevance of partial deficiency of coagulation factors

A patient suffering from cardiochalasia was found to be partially deficient in both coagulation factors V and VII. No bleeding tendency had been noticed. A family study showed that the father had factor VII deficiency with normal factor V, while the mother and 2 sisters had a reduced level of factor V and normal factor VII. Thus, the combined deficiency was due to chance association of two distinct independently segregating genetic defects. While a number of combinations of coagulation factor deficiency have been previously described, this, to be best of our knowledge, is the first instance of combined deficiency of factor V and VII reported so far.

[Partial congenital deficiency in factor V associated with an intestinal malabsorption syndrome due to lambliasis. A familial survey (author's transl)]

Owren's disease is a rare hemorrhagic diathesis which can occur in infancy as a severe hemorrhagic disorder. It also appears in adult life when clinical manifestations are those of acquired deficiencies of other coagulation factors. A familial survey enables a definite diagnosis to be made as it demonstrates the presence of deficiency in factor V in one or several members of the family. Such a case is reported in a young adult with an associated intestinal malabsorption syndrome due to lambliasis. After administration of vitamin K the deficiency in factor V remained an isolated disorder, and the hemostatic anomaly was found in three other members of the family. The deficiency was a partial one, which explains why the Owren's disease only became evident during the course of the malabsorption syndrome due to lambliasis which caused a reduction in the level of vitamin K dependent factors II, VII, and X.

Congenital factor V deficiency. A family study

A 14-month-old girl suffering from a heavy bleeding tendency, caused by a severe isolated congenital factor V deficiency is described. In this study 56 family members were examined. 10 of them had a factor V level ranging 26-60% of the normal--these were classified as heterozygotes. The case histories of the heterozygotes did not reveal a bleeding tendency. The inheritance of this factor V deficiency is autosomal recessive, with varying expressivity in the heterozygotes.

Inherited combined deficiency of factor V and factor VIII: report of a case with normal factor VIII antigen and ristocetin-induced platelet aggregation

A patient with inherited combined deficiency of factor V and factor VIII is reported, who demonstrated normal levels of factor VIII antigen and plasma cofactor for ristocetin-induced platelet aggregation. The relationship of this condition to classical hemophilia and von Willebrand's disease is discussed. The data presented suggest that multiple loci on at least 2 chromosomes are necessary for the normal expression of factor VIII activity.