Haemophilia B

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Haemophilia B
PDB 1pfx EBI.jpg
Factor IX deficiency leads to Hemophilia B
Classification and external resources
Specialty Haematology
ICD-10 D67
ICD-9-CM 286.1
OMIM 306900
DiseasesDB 5561
MedlinePlus 000539
eMedicine emerg/240
Patient UK Haemophilia B
MeSH D002836

Haemophilia B (or hemophilia B) is a blood clotting disorder caused by a mutation of the factor IX gene, leading to a deficiency of factor IX. It is the second-most common form of haemophilia, rarer than haemophilia A. Haemophilia B was first recognized as a different kind of haemophilia in 1952.[1] It is sometimes called Christmas disease, named after Stephen Christmas, the first patient described with this disease.[2] In addition, the first report of its identification was published in the Christmas edition of the British Medical Journal.[3]

Signs/symptoms[edit]

The condition is marked by increased clotting time(3-8 minutes) and bleeding time(2-5 minutes).

Genetics[edit]

The factor IX gene is located on the X chromosome (Xq27.1-q27.2). It is an X-linked recessive trait, which explains why, as in haemophilia A, usually only males are affected. One in 20,000–30,000 males are affected.[citation needed]

X chromosome

In 1990, George Brownlee and Merlin Crossley showed that two sets of genetic mutations were preventing two key proteins from attaching to the DNA of people with a rare and unusual form of haemophilia B – haemophilia B Leyden – where sufferers experience episodes of excessive bleeding in childhood but have few bleeding problems after puberty.[4] This lack of protein attachment to the DNA was thereby turning off the gene that produces clotting factor IX, which prevents excessive bleeding.[5]In 2013, Merlin Crossley discovered the third and final protein causing haemophilia B Leyden.

Pathophysiology[edit]

Factor IX deficiency leads to an increased propensity for haemorrhage. This is in response to mild trauma or even spontaneously, such as in joints (haemarthrosis) or muscles.[citation needed]

Diagnosis[edit]

Treatment[edit]

Treatment (bleeding prophylaxis) is by intravenous infusion of factor IX. Factor IX has a longer half life than factor VIII (deficient in haemophilia A) and as such factor IX can be transfused less frequently.[citation needed]

History[edit]

In the early years, there were not many treatment options for people with haemophilia B. By the late 1950s and the 1960s, with newfound technology and gradual advances in medicine, pharmaceutical scientists found a way to take the factor IX from fresh frozen plasma(FFP) and give it to those with haemophilia B. Though they found a way to treat the disease, the FFP contained only a small amount of factor IX, requiring large amounts of FFP to treat an actual bleeding episode, which resulted in the patients requiring hospitalization. By the mid-1960s scientists found a way to get a larger amount of factor IX from FFP.

By the late 1960s, pharmaceutical scientists found methods to separate the factor IX from plasma, which allows for neatly packaged bottles of factor IX concentrates. With the new development, doctors have a way to dose the amount of factor IX that patients need for bleed episodes. With the rise of factor IX concentrates it became easier for patients to get treatment at home.Although these advances in medicine had a significant positive impact on the treatment of haemophilia, there were many complications that came with it. By the early 1980s, scientists discovered that the medicines they had created were transferring blood-borne viruses, such as hepatitis, and HIV, the virus that causes AIDS. With the rise of these deadly viruses, scientists had to find improved methods for screening the blood products they received from donors.

In 1982, scientists made a breakthrough in medicine and were able to clone factor IX gene. With this new development it decreased the risk of the many viruses. Although the new factor was created, it wasn't available for haemophilia B patients till 1997.[6]

European royal families[edit]

A study published in 2009 identified the blood disease affecting the royal families of Great Britain, Germany, Russia and Spain as haemophilia B on the basis of genetic markers.[7][8]

See also[edit]

References[edit]

  1. ^ "Haemophilia B (Factor IX Deficiency) information | Patient". Patient. Retrieved 2016-04-21. 
  2. ^ Christmas' disease at Who Named It?
  3. ^ Biggs R, Douglas AS, MacFarlane RG, Dacie JV, Pitney WR, Merskey C, O'Brien JR (1952). "Christmas disease: a condition previously mistaken for haemophilia". Br Med J. 2 (4799): 1378–82. doi:10.1136/bmj.2.4799.1378. PMC 2022306free to read. PMID 12997790. 
  4. ^ http://ghr.nlm.nih.gov/condition/hemophilia
  5. ^ Crossley, M; Brownlee, G. G. (1990). "Disruption of a C/EBP binding site in the factor IX promoter is associated with haemophilia B". Nature. 345 (6274): 444–6. doi:10.1038/345444a0. PMID 2342576. 
  6. ^ "Hemophilia: From Plasma to Recombinant Factors". www.hematology.org. 2014-03-19. Retrieved 2016-05-09. 
  7. ^ Michael Price (8 October 2009). "Case Closed: Famous Royals Suffered From Hemophilia". ScienceNOW Daily News. AAAS. Retrieved 9 October 2009. 
  8. ^ Evgeny I. Rogaev; et al. (8 October 2009). "Genotype Analysis Identifies the Cause of the "Royal Disease"". Science. Retrieved 9 October 2009. 

Further reading[edit]

  • Konkle, Barbara A.; Josephson, Neil C.; Nakaya Fletcher, Shelley (1 January 1993). "Hemophilia B". GeneReviews(®). University of Washington, Seattle. Retrieved 25 June 2016. update 2014

External links[edit]