Congenital afibrinogenemia

Congenital afibrinogenemia is a rare, genetically inherited blood fibrinogen disorder in which the blood does not clot normally due to the lack of fibrinogen, a blood protein necessary for coagulation.[1] This disorder is autosomal recessive, meaning that two unaffected parents can have a child with the disorder.[2] The lack of fibrinogen expresses itself with excessive and, at times, uncontrollable bleeding.[3]

Congenital afibrinogenemia
SpecialtyHematology 

Signs and symptoms

As this is a disorder that is present in an individual from birth, there are no warning signs to look for. The first symptom usually seen is hemorrhage from the umbilical cord that is difficult to stop.[2]

Other symptoms include:[4]

Spontaneous bleeding of the mouth, nose, and gastrointestinal tract are common. Since blood clots can not be formed, minor injuries tend to lead to excessive bleeding or bruising. The biggest concern for individuals with afibrinogenemia is CNS hemorrhage, bleeding in the brain, which can be fatal. Many of these symptoms are chronic, and will continue to occur for the entirety of the affected individual's life.

Causes

A missense or nonsense mutation to the genes that code for the fibrinogen protein are affected. Usually the mutation leads to an early stop in the production of the protein.[3] Due to the problem being genetically based, there is no way to prevent the disease. Individuals can get genetic testing done to see if they are a carrier of the trait, and if so may choose to complete genetic counseling to better understand the disorder and help manage family planning. Parents can choose to do prenatal genetic testing for the disorder to determine if their child will have the disease.[6] The only risk factor is if both parents of a child carry the recessive allele linked to the disorder.

Mechanism

Individuals with the disorder have a mutation to their fibrinogen gene that prevents the formation of the protein.[3] In normal conditions, fibrinogen is converted to fibrin when it is cleaved by the enzyme thrombin in the blood. The newly formed fibrin forms a fiber-rich network that helps trap red blood cells to start the coagulation process and form a clot.[7] Since there is no fibrinogen present during afibrinogenemia, fibrin can not be formed to aid in this process.

Diagnosis

Diagnostic tests

When a problem of fibrinogen is suspected, the following tests can be ordered:

Blood fibrinogen levels of less than 0.1 g/L and prolonged bleeding test times are indicators of an individual having afibrinogenemia.[2]

Treatment

The most common treatments are transfusions of cryoprecipitate or blood plasma to help with bleeding episodes or prior to surgery.[9] There are no known cures or forms of holistic care to date. Most complications arise from the symptoms of the disorder.[5]

Prognosis

As there is not much data out on the life expectancy of an individual with afibrinogenemia, it is difficult to determine the average lifespan. However, the leading cause of death thus far is linked to CNS hemorrhage and postoperative bleeding.[5]

History

It was first described in 1920 by German doctors, Fritz Rabe and Eugene Salomon, studying a bleeding disorder presenting itself in a child from birth.[10] This disorder may also be simply called afibrinogenemia or familial afibrinogenemia.[4] About 1 in 1 million individuals are diagnosed with the disease; typically at birth.[11] Both males and females seem to be affected equally,[2] but it has a higher occurrence in regions where consanguinity is prevalent.[4]

Research

Currently research is based in pharmacological treatments.[12] A case from 2015 was seen in which congenital afibrinogenemia was resolved in a patient after receiving a liver transplant.[13] Further research must be completed.

See also
  • Factor I Deficiency

References
  1. Neerman-Arbez, Marguerite; De Moerloose, Philippe (2007). "Mutations in the fibrinogen gene cluster accounting for congenital afibrinogenemia: An update and report of 10 novel mutations". Human Mutation. 28 (6): 540–53. doi:10.1002/humu.20483. PMID 17295221.
  2. "Inherited Abnormalities of Fibrinogen: Background, Pathophysiology, Epidemiology". 2019-10-20. Cite journal requires |journal= (help)
  3. Vu, Dung; Bolton-Maggs, Paula H. B.; Parr, Jeremy R.; Morris, Michael A.; Moerloose, Philippe de; Neerman-Arbez, Marguerite (2003-12-15). "Congenital afibrinogenemia: identification and expression of a missense mutation in FGB impairing fibrinogen secretion". Blood. 102 (13): 4413–4415. doi:10.1182/blood-2003-06-2141. ISSN 0006-4971. PMID 12893758.
  4. "Congenital Afibrinogenemia". DoveMed. Retrieved 2015-11-12.
  5. "Afibrinogenemia | Disease | Your Questions Answered | Genetic and Rare Diseases Information Center (GARD) – an NCATS Program". rarediseases.info.nih.gov. Retrieved 2015-11-12.
  6. Neerman-Arbez, Marguerite; Vu, Dung; Abu-Libdeh, Bassam; Bouchardy, Isabelle; Morris, Michael A. (2003-05-01). "Prenatal diagnosis for congenital afibrinogenemia caused by a novel nonsense mutation in the FGB gene in a Palestinian family". Blood. 101 (9): 3492–3494. doi:10.1182/blood-2002-10-3116. ISSN 0006-4971. PMID 12511408.
  7. McDowall, Jennifer (November 2006). "Fibrinogen". InterPro : Classification of protein families. Retrieved 7 July 2020.
  8. Dysfibrinogenemia at eMedicine
  9. "Congenital afibrinogenemia". www.pennmedicine.org. Retrieved 2015-11-12.
  10. "Factor I deficiency (Fibrinogen deficiency) - Canadian Hemophilia Society". www.hemophilia.ca. Retrieved 2015-11-12.
  11. "Congenital afibrinogenemia". Genetics Home Reference. 2015-11-09. Retrieved 2015-11-12.
  12. "Search of: afibrinogenemia - List Results - ClinicalTrials.gov". clinicaltrials.gov. Retrieved 2015-12-10.
  13. Gallastegui, N.; Kimble, E. L.; Harrington, T. J. (2015-09-01). "Resolution of fibrinogen deficiency in a patient with congenital afibrinogenemia after liver transplantation". Haemophilia. 22 (1): e48–e51. doi:10.1111/hae.12802. ISSN 1365-2516. PMID 26421965.
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