Haemophilia B

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Haemophilia B Classification and external resources
ICD-10	D67.
ICD-9	286.1
OMIM	306900
DiseasesDB	5561
MedlinePlus	000539
eMedicine	emerg/240
MeSH	D002836

Haemophilia B (also spelled Hemophilia B or Hæmophilia 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 least common form of haemophilia, rarer than haemophilia A. It is sometimes called Christmas disease after Stephen Christmas, the first patient described with this disease.^[1] In addition, the first report of its identification was published in the Christmas edition of the British Medical Journal.^[2]

Contents 1 Treatment 2 Genetics 3 Pathophysiology 4 References 5 See also 6 External links

[edit] Treatment

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.

[edit] Genetics

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, only males are usually affected.

[edit] Pathophysiology

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.

[edit] References

1. ^ Christmas' disease at Who Named It
2. ^ 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. PMID 12997790. 

[edit] See also

• Haemophilia
• Haemophilia A
• Haemophilia C

[edit] External links

• Haemophilia: What is it? at CSHL Your Genes, Your Health
• haemophilia B at GPnotebook
• Factor IX Deficiency at FPnotebook

v • d • e Pathology: hematology, hematologic disease (primarily D50-D77, 280-289) RBCs/anemia/ hemoglobinopathy (Myeloid) nutritional anemia: Iron deficiency anemia, Plummer-Vinson syndrome, Megaloblastic anemia (Pernicious anemia) hereditary hemolytic anemia: enzyme disorders (G6PD Deficiency, Pyruvate kinase deficiency,Triosephosphate isomerase deficiency), Thalassemia, Sickle-cell disease/trait, Hereditary spherocytosis, Hereditary elliptocytosis, Hereditary stomatocytosis acquired hemolytic anemia: Autoimmune (Warm), HUS, MAHA, PNH, PCH aplastic anemia: Acquired PRCA, Diamond-Blackfan anemia, Fanconi anemia • Sideroblastic anemia Polycythemia - Methemoglobinemia Coagulation/platelets (Myeloid) coagulopathy: DIC (Congenital afibrinogenemia, Purpura fulminans) • Hemophilia (A/VII, B/IX, C/XI, XIII) • Von Willebrand disease • Hypoprothrombinemia Purpura: Henoch-Schönlein, ITP (Evans syndrome), TTP primary hypercoagulable state: Protein C deficiency - Protein S deficiency - Antithrombin III deficiency - Factor V Leiden - Activated protein C resistance - Antiphospholipid syndrome other hemorrhagic conditions: Bernard-Soulier syndrome - Glanzmann's thrombasthenia - Grey platelet syndrome - May Hegglin anomaly - Pelger-Huet anomaly Essential thrombocytosis - Thrombocytopenia Monocytes/Macrophages (Myeloid) WHO-I histiocytosis (Langerhans cell histiocytosis) WHO-II/non-Langerhans-cell histiocytosis (Juvenile xanthogranuloma, Hemophagocytic lymphohistiocytosis) WHO-III/malignant histiocytic disorders (Acute monocytic leukemia, Malignant histiocytosis, Erdheim-Chester disease) -cytosis: Monocytosis -penia: Monocytopenia Granulocytes (Myeloid) -cytosis: granulocytosis (Neutrophilia, Eosinophilia, Basophilia) -penia: Granulocytopenia/agranulocytosis (Neutropenia, Kostmann syndrome) Other/general myeloid Chronic granulomatous disease Lymphoid -cytosis: Lymphocytosis -penia: Lymphopenia Other Splenic disease (Asplenia/hyposplenism, Wandering spleen) - Pancytopenia See also hematological malignancy and immune disorders