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At least 19 recordsLinked to original sources
PubMed1990

Molecular defect (Gla+14----Lys) and its functional consequences in a hereditary factor X deficiency (factor X "Vorarlberg").

Factor X (FX) "Vorarlberg" is a congenital FX deficiency characterized clinically by a mild bleeding tendency. Homozygous individuals have a FX activity of less than 10% in the extrinsic system and 25% in the intrinsic system. FX antigen is 20%. Using molecular techniques, two point mutations were detected in the coding sequence of the FX Vorarlberg gene: a G----A at base pair 160 in exon II resulting in a change of Gla14 (GAA) to Lys (AAA); a G----A at base pair 424 in exon V resulting in a change from Glu102 (GAG) to Lys (AAG). The mutations abolished a TaqI restriction site in exon II and an MnlI site in exon V. To determine whether these mutations are present on one or on both alleles, restriction analyses of amplified exon II and exon V fragments were performed. Analysis of the pedigree showed that the genotype for the mutation on exon II (homozygous versus heterozygous) correlates with the severity of the phenotypic coagulation defect. We therefore conclude that the mutation in exon II is responsible for the functional defect in FX Vorarlberg. We have also purified the mutant FX protein from patient plasma. Purified FX Vorarlberg is indistinguishable from normal FX on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Its activity is 15% of normal FX upon activation with factor VIIa/tissue factor, 75% upon activation with factor IXa/factor VIIIa, and 100% upon activation with RVV. Activation at varying Ca2+ concentrations shows that the affinity of FX Vorarlberg for Ca2+ is decreased. Factor Xa Vorarlberg is able to convert prothrombin at a normal rate but also shows decreased affinity for Ca2+ in this interaction. Upon addition of Ca2+, FX Vorarlberg does not undergo the same conformational change as normal FX. Our data show that FX Vorarlberg has a decreased affinity for Ca2+ which impedes a normal conformational change. This leads to a decreased rate of activation by factor VIIa/tissue factor and by factor IXa. The decrease is much more marked for the extrinsic than for the intrinsic pathway.

Amino Acid Sequence↗
PubMed1976

Platelet aggregation and adhesiveness in classical factor X deficiency and in the abnormal factor X (factor X Friuli) coagulation disorder.

Platelet aggregation to common inductors and to Ristocetin, Thrombofax and Ionophore is normal in congenital factor X deficiency and in factor X Friuli coagulation disorders. Washed normal platelets resuspended in the patient's plasma and in adsorbed normal plasma showed a normal aggregation. On the contrary, normal platelets resuspended in normal serum failed to aggregate. These studies indicate that factor X plays no role in normal platelet aggregation.

Adenosine Diphosphate↗
PubMed1991

Coincidence of acquired factor-X deficiency and disseminated intravascular coagulation in patients with acute nonlymphoblastic leukemia.

Systematic clotting studies were performed in 157 patients with de novo acute nonlymphoblastic leukemia (ANLL) prior to treatment. Sixteen patients had disseminated intravascular coagulation (DIC). Three of the patients with DIC (two with M3, one with M5 leukemia) had a marked isolated factor-X deficiency (factor X:C 21%, 33%, and 41%, respectively). Another four patients had a mild isolated factor-X deficiency (factor X:C 55%-68%). In these seven patients the remaining liver-synthesized clotting factors (factors II, VII, IX, V) as well as serum albumin and cholinesterase were within the normal range. Liver disease or vitamin-K deficiency could therefore be excluded. In none of the 141 patients without DIC was a marked isolated factor X deficiency observed; two patients had moderately reduced factor X:C levels but normal liver-synthesized proteins. Induction treatment led to the control of DIC with an almost parallel increase of fibrinogen and factor X up to normal in all patients with factor-X deficiency who achieved complete remission. In one patient, recurrence of leukemia was associated with reoccurrence of DIC and marked factor-X deficiency. We conclude that there is a coincidence of isolated factor-X deficiency and DIC in some patients with ANLL. In some patients, this factor-X deficiency may be severe enough to contribute to the bleeding tendency.

Adult↗
PubMed1992

Recurrent, isolated factor X deficiency in myeloma: repeated normalization of factor X levels after cytostatic chemotherapy followed by late treatment failure associated with the development of systemic amyloidosis.

We describe the case of a 64-year-old woman with isolated severe factor X deficiency associated with kappa light chain myeloma. At the time of diagnosis there was no evidence for amyloidosis. Complete remission (CR) of myeloma as well as normalization of factor X levels were achieved after cytostatic chemotherapy. Subsequently, factor X deficiency recurred twice without any evidence for relapse of myeloma. The first time factor X normalized again following cytostatic treatment, the second time, however, factor X deficiency was refractory to chemotherapy. Finally, relapse of myeloma became evident associated with rapidly progressing, systemic amyloidosis, which was fatal within a few months. Initially, factor X infusion studies showed a normal recovery, but when amyloidosis became overt the recovery decreased to 0%. We assume that factor X deficiency was due to a binding of factor X to kappa light chains associated with the proliferation of the malignant myeloma cell clone.

Amyloidosis↗
PubMedDate not supplied

Neonatal congenital Factor X deficiency.

Four neonates with congenital Factor X deficiency presented soon after birth with bleeding episodes. Two of the newborns had intracranial hemorrhages; one of them also had antenatal ventricular dilatation and postnatal hydrocephalus and died of massive intracerebral hemorrhage at four months. One patient was lost for follow up. The two surviving infants were followed up for four years and two years respectively, while on replacement therapy with three injections of 40 units/kg prothrombin complex a month. In spite of markedly elevated prothrombin time and partial thromboplastin time, these two infants remain free of major bleeding manifestations except for troublesome petechiae and ecchymoses. A schedule for substitution therapy with Factor X is proposed for infants and children to prevent bleeding in severe Factor X deficiency.

Blood Coagulation Factors↗
PubMed1977

Acquired factor X deficiency and amyloidosis.

A selective acquired Factor X deficiency is an unusual occurrence. Six cases of an acquired Factor X deficiency in association with amyloidosis have been reported. This paper describes two additional cases, suggesting that this relationship may be more than coincidental. The mechanism by which amyloid may affect Factor X levels remains unknown, but suggestions include consumption, inactivation or decreased synthesis of Factor X. Factor II, VII, IX, and X concentrate transiently increased the Factor X level to normal in one of the patients. In an adult patient who has an isolated Factor X deficiency, amyloidosis should be actively sought.

Amyloidosis↗
PubMed1991

A case of acquired factor X deficiency with in vivo and in vitro evidence of inhibitor activity directed against factor X.

A 67-year-old woman had symptoms of an upper respiratory tract infection for which she received a five-day course of erythromycin. Epistaxis and gross hematuria subsequently developed, and the patient was found to have a selective Factor X deficiency. She received supportive therapy and prothrombin complex concentrates (Factors II, VII, IX, and X), with subsequent resolution of her transient Factor X deficiency. Her hospital course, however, was complicated by the development of multiple cerebral infarctions. This is the tenth reported case of transient Factor X deficiency not associated with amyloidosis. In seven of the previous cases, as in this patient, the deficiency was associated with a preceding upper respiratory infection. This is the only case, however, with evidence of inhibitory activity in the plasma that was directed toward Factor X.

Aged↗
PubMed1977

Syndrome of acquired factor X deficiency and systemic amyloidosis; in vivo studies of the metabolic fate of factor X.

To determine the metabolic fate of factor X in primary amyloidosis associated with factor X deficiency, we examined the pathways of its catabolism in a man with this syndrome. Intravenous infusion of human or bovine 131I-labeled factor X established a triphasic plasma clearance pattern for factor X. About 85 per cent of the factor X disappeared, with a disappearance half-time of less than 30 seconds. A second and third phase showed a T1/2 of 90 minutes and nine hours respectively. 131I-labeles factor X in plasma did not appear to be rapidly modified or degraded. Relatively minor quantities of 131I were cleared into the urine. We observed a diffuse distribution of radioactivity over the body surface, with a concentration in the hepatic and splenic regions. These studies demonstrate than factor X deficiency associated with systemic amyloidosis is due to binding of factor X to body tissue, probably within the circulatory system.

Amyloidosis↗
PubMed1985

Heterogeneity of hereditary and acquired factor X deficiencies by combined immunochemical and functional analyses.

Limited information is available regarding molecular abnormalities associated with derived factor X deficiencies. In order to assess the types of molecular aberrations that may occur in this group of haemostatic diseases we have analysed plasmas of 33 individuals from 28 kindred exhibiting factor X deficiency. These included those of hereditary type, transiently acquired deficiency as well as factor X deficiency associated with amyloidosis. Plasmas were analysed by one-stage assays for factor X activation by the extrinsic coagulation pathway, intrinsic coagulation pathway and Russell's viper venom. Selected plasmas were analysed in two-stage assays. Normal factor X concentration by specific radioimmunoassay was 6.38 +/- 1.29 micrograms/ml. Factor X associated with factor X deficiency were grouped by their specific activities measured for the three activation pathways and antigen concentration. The results suggest that a broad spectrum of molecular aberrations exist in the factor X deficiency states. The most common group of factor X deficiency was associated with abnormal activation of factor X by all three pathways. Variants of factor X associated with primary amyloidosis and transient acquired deficiency appeared to be abnormal molecules and not just reduced factor X concentration. Hereditary abnormal factor X molecules include the spectrum of potential defective molecules. The relationship of factor X structure to function and the heterogeneity of these defective molecules is discussed.

Antigens↗
PubMed1975

Classical factor X deficiency. Report of a further case.

A case of classical factor X deficiency is reported. The propositus is a 28-year-old male who presented easy bruising, epistaxis, hematomas, hematuria and occasional hemartrosis since early childhood. The severely prolonged prothrombin time was corrected by normal serum but not by adsorbed normal plasma. The abnormality was not corrected by the plasma of a patient with factor X deficiency, but by the plasma of patients with factor II or VII deficiencies. Partial thromboplastin time, prothrombin consumption and the thromboplastin generation test were abnormal. The thromboelastogram showed a prolonged 'K' and 'r' together with a normal 'ma'. Factor X was very low (smaller than 1%). Platelet tests were normal. No factor X band or precipitates were seen on electroimmunoassay and on the cross-over electrophoresis. The non-consanguineous parents and several other members of the family were found to be heterozygotes.

Adult↗
PubMed1989

Transient acquired factor X deficiency: report of the use of activated clotting concentrate to control a life-threatening hemorrhage.

Acquired deficiency of factor X is an uncommon occurrence. It has usually developed in association with amyloidosis [8] and, in that setting, it has been irreversible. Transient deficiency appears to be associated with an acute respiratory infection in the majority of cases. Bleeding in these patients can be life-threatening and has been difficult to control. Konyne produces a brief correction of the prothrombin time and an elevation in the factor X level, but has not been effective in stopping bleeding. We report the first successful correction of prothrombin time and clinical resolution of bleeding attending the use of Autoplex T. If bleeding persists after appropriate specific factor replacement and the clinical condition warrants, the use of Autoplex T (activated prothrombin complex) deserves prompt consideration.

Aged↗
PubMed1986

Severe congenital factor X deficiency with intracranial haemorrhage.

A Saudi Arabian infant with severe factor X deficiency who had had two intracranial haemorrhages is described. Attempts to raise his factor X level and improve his prothrombin time (PT) and partial thromboplastin time (PTT) by using vitamin K, oestradiol and danazol have failed. New therapeutic trials are necessary for patients with severe forms of this rare disorder.

Blood Transfusion↗
PubMedDate not supplied

Replacement therapy for congenital Factor X deficiency.

We studied a young woman with severe (less than 1%) congenital factor X deficiency during a 2-year period in order to document the levels of factor X required to provide hemostasis for vaginal bleeding, epistaxis, and hemarthroses, as well as during surgery. Factor X levels of 9 to 17 percent, achieved with fresh-frozen plasma (FFP) were satisfactory for minor bleeding. Hemostasis was achieved during emergency surgery for hemoperitoneum by increasing the factor X level to 35 percent with a Factor IX concentrate, followed with infusions of FFP to maintain levels between 10 and 20 percent for 6 days postoperatively. These data suggest that factor X levels of 10 to 20 percent are sufficient for hemostasis in factor X-deficient patients even in the immediate postoperative period.

Adult↗
PubMed1989

Partial gene deletion in a family with factor X deficiency.

The presence of gene lesions in coagulation factor X (FX, Stuart factor) was investigated in patients with FX deficiency or an FX abnormality (FX Friuli). The proposita had a heterozygous partial deletion of the FX gene with severe deficiency of FX activity and antigen. The lesion, which was inherited from her mother, removes the 3' portion of the gene coding for the catalytic domain of the factor. In this family, two differently affected FX genes are present, leading to double heterozygosity of the proposita and thus excluding consanguinity of parents. An apparently normal gene structure was observed in the other patient with FX abnormality, suggesting the presence of a small gene lesion.

Alleles↗
PubMed1991

Molecular genetic analysis of factor X deficiency: gene deletion and germline mosaicism.

A case of homozygous factor X deficiency arising from the inheritance of two non-identical gene deletions from heterozygous parents is described. One, a partial gene deletion, was localized to exons VII and VIII by a combination of Southern blotting and polymerase chain reaction (PCR) amplification of exon sequences. The other deletion, of maternal origin, probably involves the entire factor X gene. Restriction fragments associated with the exon VII + VIII deletion were present in three siblings including the homozygous proband. These fragments were however absent from the somatic cells of the father, a finding consistent with germline mosaicism.

Base Sequence↗
PubMed1976

Treatment of amyloidosis associated factor X deficiency.

This is the tenth patient in thirteen years to be reported with the findings of an isolated factor X deficiency associated with primary amyloidosis. A favorable response to factor IX concentrate was manifested by temporary clinical and laboratory correction of her diathesis. This mode of treatment, therefore, provides an approach to therapy for bleeding complications in this group of patients who have previously failed to response to fresh frozen plasma.

Amyloidosis↗