Factor XII deficiency

Factor XII deficiency is a deficiency in the production of factor XII (FXII), a plasma glycoprotein and clotting factor that participates in the coagulation cascade and activates factor XI. FXII appears to be not essential for blood clotting, as individuals with this condition are usually asymptomatic and form blood clots in vivo. FXII deficiency tends to be identified during presurgical laboratory screening for bleeding disorders.[1]

Factor XII deficiency
Other namesHageman factor deficiency
SpecialtyHematology, medical genetics 

The condition can be inherited or acquired.

Symptoms

While it is indicated that people with FXII deficiency are generally asymptomatic,[2] studies in women with recurrent miscarriages suggest an association with FXII deficiency.[3]The condition is of importance in the differential diagnosis to other bleeding disorders, specifically the hemophilias: hemophilia A with a deficiency in factor VIII or antihemophilic globulin, hemophilia B with a deficiency in factor IX (Christmas disease), and hemophilia C with a deficiency in factor XI. Other rare forms of bleeding disorders are also in the differential diagnosis.

There is concern that individuals with FXII deficiency are more prone to thrombophilic disease,[1] however, this is at variance with a long term study from Switzerland.[4]

Causes

Inherited or congenital FX deficiency is usually passed on by autosomal recessive inheritance.[2] A person needs to inherit a defective gene from both parents. People who have only one defective gene are asymptomatic, but may have lower FXII levels and can pass the gene on to half their offspring.

In persons with congenital FXII deficiency the condition is lifelong. People affected may want to alert other family members as they may also carry the gene. A 1994 study of 300 healthy blood donors found that 7 persons (2.3%) had FXII deficiencies with one subject having no detectable FXII (0.3%).[5] This study is at variance with estimates that only 1 in 1,000,000 people has the condition.[2]

The acquired form of FXII deficiency is seen in patients with the nephrotic syndrome, liver disease, sepsis and shock, disseminated intravascular coagulation, and other diseases.[1]

Diagnosis

The condition is diagnosed by blood tests in the laboratory when it is noted that special blood clotting test are abnormal. Specifically prothrombin time (PT) or activated partial thromboplastin time(aPTT) are prolonged.[2] The diagnosis is confirmed by an assay detecting very low or absent FXII levels.

The FXII (F12) gene is found on chromosome 5q33-qter.[2]

In hereditary angioedema type III an increased activity of factor XII has been described.[6]

Treatment

In congenital FXII deficiency treatment is not necessary. In acquired FXII deficiency the underlying problem needs to be addressed.

History

The condition was first described in 1955 based by blood testing of a patient named John Hageman.[7]

References
  1. Riley RS (April 2005). "Factor XII Deficiency" (PDF). Pathology, Virginia Commonwealth University. Retrieved February 20, 2017.
  2. "Factor XII Deficiency". National Organization for Rare Disorders(NORD). Retrieved February 20, 2017.
  3. Pauer HU, Burfeind P, Köstering H, Emons G, Hinney B (2003). "Factor XII deficiency is strongly associated with primary recurrent abortions". Fertility and Sterility. 80 (3): 590–594. doi:10.1016/S0015-0282(03)00788-X.
  4. Zeerleder S, Schloesser M, Redondo M, Wuillemin WA, Engel W, Furlan M, Laemmle B (1999). "Reevaluation of the Incidence of Thromboembolic Complications in Congenital Factor XII Deficiency A Study on 73 Subjects from 14 Swiss Families". Thrombosis and Haemostasis. 82 (4): 1240–1246. doi:10.1055/s-0037-1614368. Retrieved February 20, 2017.
  5. Halbmayer WM, Haushofer A, Schoen R, Mannhalter C, Strohmer E, Baumgarten K, Fischer M (1994). "The prevalence of moderate and severe FXII (Hageman factor) deficiency among the normal population: evaluation of the incidence of FXII deficiency among 300 healthy blood donors". Thromb Haemost. 71 (1): 68–72. doi:10.1055/s-0038-1642386. PMID 8165648.
  6. Cichon S, Martin L, Hennies HC, Müller F, Van Driessche K, Karpushova A, Stevens W, Colombo R, Renné T, Drouet C, Bork K, Nöthen MM (2006). "Increased Activity of Coagulation Factor XII (Hageman Factor) Causes Hereditary Angioedema Type III". Am J Hum Genet. 79 (6): 1098–1104. doi:10.1086/509899. PMC 1698720. PMID 17186468.
  7. Ratnoff OD, Margolius A (1955). "Hageman trait: an asymptomatic disorder of blood coagulation". Transactions of the Association of American Physicians. 68: 149–54. PMID 13299324.
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