Congenital haemorrhagic condition similar but not identical to factor X deficiency. A haemorrhagic state due to an abnormal factor X?

Factor X Friuli Coagulation Disorder: Almost 50 Years Later

The story of factor X (FX) Friuli. Factor X Friuli was discovered in 1969 to 1970. However, the story of that disease was an international event since patients with this defect were studied in France and in Italy, and different diagnoses were reached-FVII; FX; combined prothrombin complex; and combined FII, FVII, and FX deficiencies. The diagnostic difficulties were due to the peculiar clotting pattern presented by these patients, namely, prolonged partial thromboplastin time, prolonged prothrombin time but normal Russell viper venom clotting time. Only suitable anti-FX antisera clarified the pattern. Altogether 12 homozygotes and 102 heterozygotes have been followed during 4 decades. Six homozygotes died, 2 of them due to HIV infection and 1 due to hepatitis B liver cirrhosis. The other 3 died of nontransfusion-related morbidity. Bleeding tendency has been moderate in agreement with the extrinsic or intrinsic system assay results-FX level of 4% to 5% is considered normal. Heterozygotes may present occasional bleeding manifestations usually during surgery or delivery. Molecular analysis have shown that the mutation responsible for the defect is a Pro343Ser substitution in exon 8. Chimeric FX Friuli mice have been useful in studying the effect of FX levels on embryonic or natal mortality of these animals. No new homozygote but several heterozygotes have been recently seen. The study of FX Friuli has revolutionized the diagnostic approach to FX deficiencies. The FX should be assayed by all assay systems. The FX Friuli has never been described in any other country, and all patients studied come from the Friuli Meduna River Valley.

Novel factor X deficiency. Normal partial thromboplastin time and associated spindle cell thymoma

This report presents a heretofore undescribed laboratory variant of congenital factor X deficiency, seen in conjunction with a relatively rare tumor. The patient had a history of bleeding, a prolonged prothrombin time, and a factor X value of 4.2 percent of normal activity, but the partial thromboplastin time and Russell's viper venom clotting time were normal. Management of this case required unusual measures to treat the patient's coagulopathy.

Inherited factor X deficiency: presentation of a case with etiologic and treatment considerations

The first documented case of inherited factor X deficiency in the dental literature is presented. Its ascertainment as a result of postoperative surgical complications illustrates the clinician's need to be familiar with the hereditary bleeding diatheses, as treatment is dependent on the underlying etiology of the specific disorder. In the present case treatment included administration of the antifibrinolytic agent epsilon-aminocaproic acid (EACA) and fresh frozen plasma. On the basis of our findings, a minimal therapeutic level of circulating factor X is estimated to be 15 percent of the normal level. Genetic heterogeneity within the factor X deficiency phenotype is discussed and, on the basis of laboratory findings, a CRM-positive autosomal recessive structural or regulator gene defect is proposed as the etiologic factor in the current case. Forty-nine cases in the literature are reviewed to delineate the pattern of bleeding in hereditary factor X deficiency.

A family with heterozygous factor X Friuli defect outside Friuli

Three members of the same family were found to have a clotting defect consistent with the diagnosis of heterozygous factor X Friuli disorder. The main features of the defect were a mild prolongation of prothrombin time and partial thromboplastin time, but a normal Stypven-Cephalin clotting time. Factor X activity was 40-50% of normal using tissue thromboplastin, but was perfectly normal using Russell's viper venom and cephalin. Using chromogenic substrate S-2222 the level was 30% of normal. Immunologically, factor X was normal. Bleeding manifestations were mild if any. The hereditary pattern was autosomal. The family comes from an area far away from Friuli and represents the first example of factor X Friuli discovered outside the Friuli.

New methods in coagulation

Recent advances in the elucidation of the molecular biochemistry of the coagulation proteins have provided the foundation for the development of synthetic substrates. These substrates are oligopeptide with either a chromophore or fluorophore group attached to the C-terminal end. They may be used in the laboratory to assay for a number of the serine proteases involved in either coagulation or fibrinolysis. Also, by suitably modifying the assay system, the various inhibitors can be quantitated. These substrates promise to revolutionize the coagulation laboratory allowing for more precise quantitation of trace enzymes and also improved standardization and precision of coagulation assays. In addition to these substrates, the introduction of a number of immunologic procedures into the diagnostic laboratory have been of major importance in elucidating the heterogeneity of hereditary coagulation defects. By correlating the immunologic assays, coagulation assays and clinical picture, a number of subgroups of hereditary deficiencies have been identified. Also, the immunologic assays have provided a means for identifying the carrier state of hemophilia A and have significantly contributed to the improved diagnosis of von Willebrand's disease. The use of ristocetin cofactor assays, when used in conjunction with the Factor VIII antigens, have enable the laboratory to more accurately diagnose the majority of patients with von Willebrand's disease. Ristocetin cofactor may be assayed utilizing either formalin fixed or washed platelets and recently a snake venom has been introduced to assay for this particular aspect of the Factor VIII complex. Platelet specific proteins (i.e., platelet factor 4 and beta-thromboglobulin) may be assayed utilizing either radioimmunoassays or in the case of platelet factor 4 modified coagulation assays. These proteins provide evidence of in vivo platelet activation and hopefully may, in the future, be correlated with platelet kinetics.

Factor X Friuli: An immunological study in plasma and in serum using several methods

An immunological study of factor X Friuli was carried out using an anti-human-factor X antiserum. The results obtained with different methods were compared. Only an ill-defined factor X band or precipitate was evident on standard immuno-electrophoresis and on immunodiffusion. Using a non-absorbed antiserum a precipitate was evident on eletroimmunoassay, in normal, factor X Friuli and in factor X deficient plasma. On the contary, using an antiserum which had been previously absorbed with factor X deficient plasma, a precipitate was evident only with factor X Friuli plasma or normal plasma. Excellent results were obtained with the cross-over electrophoresis. Using this method a major or factor X band was evident in normal plasma, factor II,P FACTOR VII, factor IX deficient plasmas and in the factor X FRIULI PLASMA. No factor X band was evident in factor X deficient plasmas and in absorbed normal plasma. Lighter, more cathodic bands were seen in all plasmas. These were due to secondary activities of the antiserum and could be disregarded. Friuli serum factor X and normal serum factor X showed a slightly more anodic migration as compared to their plasma counterparts. In coumarin plasma two factor X bands were evident; one normal in position and one slightly more catholidic. In the bidimensional immunoelectrophoresis two precipitates are visible in normal plasma and in factor X Friuli plasma. In factor X deficient plasma only one precipitate is evident. This latter precipitate is due to the secondary activity of the antiserum used. On the basis of these data it is concluded that factor X Friuli behaves, immunologically, as normal factor X.