Factor Xa is a vitamin K-dependent glycoprotein that converts prothrombin to thrombin in the presence of factor Va, calcium and phospholipid during blood clotting. (updated: Oct. 10, 2018)
The data and differentiation stages presented below come from the proteomic study and analysis performed by our partners of the GReX consortium, more details are available in their published work.
No sequence conservation computed yet.
This protein is annotated as membranous in Gene Ontology.
Total structural coverage: 85%
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The reference OMIM entry for this protein is 227600
Factor x deficiency
F10 deficiency
Stuart-prower factor deficiency
A number sign (#) is used with this entry because factor X deficiency is caused by homozygous or compound heterozygous mutation in the gene encoding coagulation factor X (F10; 613872).
DESCRIPTION
Factor X deficiency is a rare autosomal recessive bleeding disorder showing variable phenotypic severity. Affected individuals can manifest prolonged nasal and mucosal hemorrhage, menorrhagia, hematuria, and occasionally hemarthrosis. The disorder can be caused either by reduced levels of the factor X protein or by synthesis of a dysfunctional factor X protein (summary by Millar et al., 2000).
CLINICAL FEATURES
Girolami et al. (1970) described a congenital haemorrhagic condition due to the presence of an abnormal factor X in a large kindred from Friuli, a remote valley in northeastern Italy. Girolami et al. (1971) reported another family from Friuli with a bleeding disorder due to an abnormal factor X. The proposita was a 43-year-old woman with a history of bleeding since early childhood. She had had epistaxis, menorrhagia, bleeding after tooth extractions, gum bleeding, postpartum hemorrhage, posttraumatic hemarthroses, and hematuria. Laboratory studies showed prolonged prothrombin time (PT), prolonged partial thromboplastin time (PTT), and correction with Russell viper venom. Factor X activity was significantly decreased (6 to 9% of normal), but antigen levels were normal; however, an abnormal factor X protein was identified immunologically, indicating a qualitative deficiency. The patient's 2 children and mother had 38 to 48% activity levels, consistent with the heterozygous state. Sumer et al. (1986) reported a Saudi Arabian infant with severe factor X deficiency who had had 2 intracranial hemorrhages. De Stefano et al. (1988) reported a 13-year-old girl, born of consanguineous parents, with defective factor X. Laboratory studies showed normal factor X antigen levels, but the protein was severely impaired in activation via the intrinsic pathway (3% of normal) and partially defective in activation via the extrinsic pathway (30-50% of normal). The variant protein, termed factor X Roma, was activated by Russell viper venom. The parents of the proposita showed factor X functional levels compatible with heterozygosity for the abnormality. Millar et al. (2000) determined that the Roma variant results from a T318M substitution (
613872.0015) in the F10 gene. Peyvandi et al. (1998) studied 32 Iranian patients with congenital factor X deficiency. The most frequent symptom was epistaxis, which occurred in 72% of patients, with all degrees of deficiency. Other mucosal hemorrhages (e.g., hematuria, gastrointestinal bleeding) were less frequent and occurred mainly in patients with unmeasurable factor X. Menorrhagia occurred in half of the women of reproductive age. Soft tissue bleeding occurred in two-thirds of the patients; spontaneous hematomas and hemarthroses led to severe arthropathy in 5 patients. Bleeding from the umbilical stump was an unexpected finding in 9 patients. The study demonstrated that the bleeding tendency of factor X deficiency can be severe and correlates with factor levels. - Acquired Factor X Deficiency Furie et al. (1977) presented evidence that the acquired deficiency of factor X associated with systemic amyloidosis is caused by binding of the factor X protein to amyloid. Ashrani et al. (2003) described factor X deficiency associated with lupus anticoagulant and a bleeding diathesis. They reported 2 patien ...
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Subscribe to this protein entry history
June 30, 2020: Protein entry updated
Automatic update: OMIM entry 227600 was added.
Feb. 23, 2019: Protein entry updated
Automatic update: comparative model was added.
Feb. 23, 2019: Protein entry updated
Automatic update: model status changed
Oct. 19, 2018: Additional information
Initial protein addition to the database. This entry was referenced in Bryk and co-workers. (2017).