View source for Medicine:Haemophilia

{{short description|Genetic disease involving blood clotting}}
<!--Note that "hemophilia" is a North American spelling difference, so as per WP:ENGVAR, please leave the British spelling "haemophilia" as is.-->
{{Infobox medical condition (new)
| name          = Haemophilia
| synonyms      = [[Social:American and British English spelling differences#ae and oe|Hemophilia]]
| image         = PBB Protein F8 image.jpg
| caption       = A drawing of clotting [[Biology:Factor VIII|factor VIII]]
| field         = Haematology
| pronounce     = {{IPAc-en|h|iː|m|ə|ˈ|f|ɪ|l|i|ə}}
| symptoms      = Easy and prolonged [[Medicine:Bleeding|bleeding]]<ref name=NIH2013Sym/>
| complications =
| onset         = At birth<ref name=NIH2013What/>
| duration      =
| causes        = Usually [[Medicine:Genetic disorder|genetic]]<ref name=CDC2014/>
| risks         =
| diagnosis     = Blood test<ref name=NIH213Diag/>
| differential  =
| prevention    = Preimplantation screening<ref name=NIH213Diag/>
| treatment     = Replace missing blood clotting factors<ref name=CDC2014/>
| medication    =
| prognosis     =
| frequency     = 1 in 7,500 males (haemophilia A), 1 in 40,000 males (haemophilia B)<ref name=NIH2013What/><ref name=Wyn2009/>
| deaths        =
}}
<!-- Definition and symptoms -->
'''Haemophilia''', or '''hemophilia'''<ref>{{cite web |title=What Is Hemophilia? |url=https://www.cdc.gov/ncbddd/hemophilia/facts.html |website=cdc.gov |date=12 May 2020 |publisher=U.S. Centers for Disease Control |access-date=3 April 2021}}</ref> ({{etymology|grc|''{{wikt-lang|grc|αἷμα}}'' ({{grc-transl|αἷμα}})|blood||''{{wikt-lang|grc|φιλία}}'' ({{grc-transl|φιλία}})|love of}}),<ref>{{cite web|url=http://www.etymonline.com/index.php?search=hemophilia&searchmode=none|title=Online Etymology Dictionary|author=Douglas Harper|access-date=10 October 2007|url-status=live|archive-url=https://web.archive.org/web/20080306042235/http://www.etymonline.com/index.php?search=hemophilia&searchmode=none|archive-date=6 March 2008}}</ref> is a mostly inherited [[Medicine:Genetic disorder|genetic disorder]] that impairs the body's ability to make blood clots, a process needed to [[Medicine:Hemostasis|stop bleeding]].<ref name=NIH2013What>{{cite web|title=What Is Hemophilia?|url=https://www.nhlbi.nih.gov/health/health-topics/topics/hemophilia|website=NHLBI|access-date=8 September 2016|date=July 13, 2013|url-status=live|archive-url=https://web.archive.org/web/20161004222515/http://www.nhlbi.nih.gov/health/health-topics/topics/hemophilia|archive-date=4 October 2016}}</ref><ref name=CDC2014>{{cite web|title=Hemophilia Facts|url=https://www.cdc.gov/ncbddd/hemophilia/facts.html|website=CDC|access-date=8 September 2016|date=August 26, 2014|url-status=live|archive-url=https://web.archive.org/web/20160827085015/http://www.cdc.gov/ncbddd/hemophilia/facts.html|archive-date=27 August 2016}}</ref> This results in people [[Medicine:Bleeding|bleeding]] for a longer time after an injury, easy bruising, and an increased risk of [[Medicine:Hemarthrosis|bleeding inside joint]]s or the [[Biology:Brain|brain]].<ref name=NIH2013Sym/> Those with a mild case of the disease may have symptoms only after an accident or during surgery.<ref name=NIH2013Sym/> Bleeding into a joint can result in permanent damage while bleeding in the brain can result in long term [[Medicine:Headache|headache]]s, [[Medicine:Seizure|seizure]]s, or a decreased level of consciousness.<ref name="NIH2013Sym">{{cite web|title=What Are the Signs and Symptoms of Hemophilia?|url=https://www.nhlbi.nih.gov/health/health-topics/topics/hemophilia/signs|website=NHLBI|access-date=8 September 2016|date=July 13, 2013|url-status=live|archive-url=https://web.archive.org/web/20160917105954/https://www.nhlbi.nih.gov/health/health-topics/topics/hemophilia/signs|archive-date=17 September 2016}}</ref>

<!-- Cause and mechanism -->
There are two main types of haemophilia: haemophilia A, which occurs due to low amounts of clotting [[Biology:Factor VIII|factor VIII]], and haemophilia B, which occurs due to low levels of clotting [[Biology:Factor IX|factor IX]].<ref name=NIH2013What/> They are typically inherited from one's parents through an [[Biology:X chromosome|X chromosome]] carrying a nonfunctional [[Biology:Gene|gene]].<ref name=NIH203Cau/> Most commonly found in men, Hemophilia can affect women too, though very rarely. A woman would need to inherit two infected X chromosomes to be affected, whereas a man would only need one X chromosome affected. It is possible for a new [[Biology:Mutation|mutation]] to occur during early development, or haemophilia may develop later in life due to [[Biology:Antibodies|antibodies]] forming against a clotting factor.<ref name=NIH2013What/><ref name=NIH203Cau>{{cite web|title=What Causes Hemophilia?|url=https://www.nhlbi.nih.gov/health/health-topics/topics/hemophilia/causes|website=NHLBI|access-date=10 September 2016|date=July 13, 2013|url-status=live|archive-url=https://web.archive.org/web/20160908233612/http://www.nhlbi.nih.gov/health/health-topics/topics/hemophilia/causes|archive-date=8 September 2016}}</ref> Other types include haemophilia C, which occurs due to low levels of [[Biology:Factor XI|factor XI]], [[Medicine:Von Willebrand disease|Von Willebrand disease]], which occurs due to low levels of a substance called von Willebrand factor, and parahaemophilia, which occurs due to low levels of factor V.<ref>{{cite journal|last1=Franchini|first1=M|last2=Mannucci|first2=PM|title=Inhibitors of propagation of coagulation (factors VIII, IX and XI): a review of current therapeutic practice.|journal=British Journal of Clinical Pharmacology|date=October 2011|volume=72|issue=4|pages=553–62|pmid=21204915|doi=10.1111/j.1365-2125.2010.03899.x|pmc=3195733}}</ref><ref name=Thal2013>{{cite journal|last1=Thalji|first1=N|last2=Camire|first2=RM|title=Parahemophilia: new insights into factor v deficiency.|journal=Seminars in Thrombosis and Hemostasis|date=September 2013|volume=39|issue=6|pages=607–12|pmid=23893775|doi=10.1055/s-0033-1349224|s2cid=21053684}}</ref> Haemophilia A, B, and C prevent the intrinsic pathway from functioning properly; this clotting pathway is necessary when there is damage to the endothelium of a blood vessel.<ref>{{Cite journal |last=Camire |first=Rodney M |date=2012-01-01 |title=Bioengineered factor Xa as a potential new strategy for hemophilia therapy |url=https://doi.org/10.1586/ehm.12.13 |journal=Expert Review of Hematology |volume=5 |issue=2 |pages=121–123 |doi=10.1586/ehm.12.13 |issn=1747-4086 |pmid=22475278|s2cid=7065701 }}</ref><ref>{{Cite journal |last1=Al-Fadhil |first1=Nawal |last2=Pathare |first2=Anil |last3=Ganesh |first3=Anuradha |date=2001-10-01 |title=Traumatic Hyphema and Factor XI Deficiency (Hemophilia C) |url=https://jamanetwork.com/journals/jamaophthalmology/article-abstract/268049 |journal=Archives of Ophthalmology |volume=119 |issue=10 |pages=1546–1547 |pmid=11594962 |issn=0003-9950}}</ref><ref>{{Citation |last1=Chaudhry |first1=Raheel |title=Physiology, Coagulation Pathways |date=2022 |url=http://www.ncbi.nlm.nih.gov/books/NBK482253/ |work=StatPearls |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=29489185 |access-date=2022-11-13 |last2=Usama |first2=Syed Muhammad |last3=Babiker |first3=Hani M.}}</ref> Acquired haemophilia is associated with [[Medicine:Cancer|cancer]]s, autoimmune disorders, and [[Medicine:Pregnancy|pregnancy]].<ref>{{cite journal|last1=Franchini|first1=M|last2=Mannucci|first2=PM|title=Acquired haemophilia A: a 2013 update.|journal=Thrombosis and Haemostasis|date=December 2013|volume=110|issue=6|pages=1114–20|pmid=24008306|doi=10.1160/TH13-05-0363|citeseerx=10.1.1.684.7962|s2cid=2174637}}</ref><ref name=Mul2014>{{cite journal|last1=Mulliez|first1=SM|last2=Vantilborgh|first2=A|last3=Devreese|first3=KM|title=Acquired hemophilia: a case report and review of the literature.|journal=International Journal of Laboratory Hematology|date=June 2014|volume=36|issue=3|pages=398–407|pmid=24750687|doi=10.1111/ijlh.12210|s2cid=205194015|doi-access=free}}</ref> Diagnosis is by testing the blood for its ability to clot and its levels of clotting factors.<ref name=NIH213Diag>{{cite web|title=How Is Hemophilia Diagnosed?|url=https://www.nhlbi.nih.gov/health/health-topics/topics/hemophilia/diagnosis|website=NHLBI|access-date=10 September 2016|date=July 13, 2013|url-status=live|archive-url=https://web.archive.org/web/20160915152750/http://www.nhlbi.nih.gov/health/health-topics/topics/hemophilia/diagnosis|archive-date=15 September 2016}}</ref>

<!-- Prevention and treatment -->
Prevention may occur by removing an [[Biology:Egg cell|egg]], fertilizing it, and testing the [[Biology:Embryo|embryo]] before transferring it to the [[Biology:Uterus|uterus]].<ref name=NIH213Diag/><!-- Quote = Women who are hemophilia carriers also can have "preimplantation diagnosis" to have children who don't have hemophilia. For this process, women have their eggs removed and fertilized by sperm in a laboratory. The embryos are then tested for hemophilia. Only embryos without the disorder are implanted in the womb.--> Human embryos in research can be regarded as the technical object/process. Missing blood clotting factors are replaced to treat haemophilia.<ref name=CDC2014/> This may be done on a regular basis or during bleeding episodes.<ref name=CDC2014/> Replacement may take place at home or in hospital.<ref name=NIH2013Tx/> The clotting factors are made either from human blood or by [[Biology:Protein production|recombinant methods]].<ref name=NIH2013Tx>{{cite web|title=How Is Hemophilia Treated?|url=https://www.nhlbi.nih.gov/health/health-topics/topics/hemophilia/treatment|website=NHLBI|access-date=10 September 2016|date=July 13, 2013|url-status=live|archive-url=https://web.archive.org/web/20160917160609/https://www.nhlbi.nih.gov/health/health-topics/topics/hemophilia/treatment|archive-date=17 September 2016}}</ref> Up to 20% of people develop [[Biology:Antibodies|antibodies]] to the clotting factors which makes treatment more difficult.<ref name=CDC2014/> The medication [[Chemistry:Desmopressin|desmopressin]] may be used in those with mild haemophilia A.<ref name=NIH2013Tx/> Studies of [[Biology:Gene therapy|gene therapy]] are in early human trials.<ref name=Pey2016>{{cite journal|last1=Peyvandi|first1=F|last2=Garagiola|first2=I|last3=Young|first3=G|title=The past and future of haemophilia: diagnosis, treatments, and its complications.|journal=Lancet|date=9 July 2016|volume=388|issue=10040|pages=187–97|pmid=26897598|doi=10.1016/s0140-6736(15)01123-x|s2cid=21945676}}</ref>

<!-- Epidemiology and culture -->
Haemophilia A affects about 1 in 5,000–10,000, while haemophilia B affects about 1 in 40,000 males at birth.<ref name=NIH2013What/><ref name=Wyn2009/> As haemophilia A and B are both [[Biology:X-linked recessive inheritance|X-linked recessive disorders]], females are rarely severely affected.<ref name=NIH203Cau/> Some females with a nonfunctional gene on one of the X chromosomes may be mildly symptomatic.<ref name=NIH203Cau/> Haemophilia C occurs equally in both sexes and is mostly found in Ashkenazi Jews.<ref name=Wyn2009/> In the 1800s haemophilia B [[History:Haemophilia in European royalty|was common within the royal families of Europe]].<ref name=Wyn2009/> The difference between haemophilia A and B was determined in 1952.<ref name=Wyn2009>{{cite book|last1=Wynbrandt|first1=James|last2=Ludman|first2=Mark D.|title=The Encyclopedia of Genetic Disorders and Birth Defects|url=https://books.google.com/books?id=kXaMjwItP0oC&pg=PA194|access-date=25 August 2013|date=1 January 2009|publisher=Infobase Publishing|isbn=978-1-4381-2095-9|pages=194|url-status=live|archive-url=https://web.archive.org/web/20140108012348/http://books.google.com/books?id=kXaMjwItP0oC&pg=PA194|archive-date=8 January 2014}}</ref>

== Signs and symptoms ==
[[File:A woman suffering from Hemophilia.png|thumb|upright=1.3|An illustration of a woman with hemophilia]]

Characteristic [[Medicine:Symptom|symptom]]s vary with severity. In general symptoms are internal or external bleeding episodes, which are called "bleeds".<ref>[http://www.hemophilia.org/NHFWeb/MainPgs/MainNHF.aspx?menuid=191&contentid=382&rptname=bleeding Types of Bleeds] {{webarchive|url=https://web.archive.org/web/20100213033649/http://www.hemophilia.org/NHFWeb/MainPgs/MainNHF.aspx?menuid=191&contentid=382&rptname=bleeding |date=2010-02-13 }} National Hemophilia Foundation.</ref><ref>[http://www.haemophilia.org.uk/index.php?content_id=87&parent=278 Key facts: what is haemophilia?] {{webarchive|url=https://web.archive.org/web/20090523015116/http://www.haemophilia.org.uk/index.php?content_id=87&parent=278 |date=2009-05-23 }} The Haemophilia Society.</ref> People with more severe haemophilia experience more severe and more frequent bleeds, while people with mild haemophilia usually experience more minor symptoms except after surgery or serious trauma. In cases of moderate haemophilia symptoms are variable which manifest along a spectrum between severe and mild forms.<ref>{{cite journal | vauthors = Benson G, Auerswald G, Dolan G, Duffy A, Hermans C, Ljung R, Morfini M, Šalek SZ | title = Diagnosis and care of patients with mild haemophilia: practical recommendations for clinical management
 | journal = Blood Transfusion
 | publisher = Blood Transfus. | date=November 2018 | volume = 16 | issue = 6 | pages = 535–544
 | doi=10.2450/2017.0150-17 | pmid = 29328905| pmc = 6214819
 }}</ref>

In both haemophilia A and B, there is spontaneous bleeding but a normal bleeding time, normal [[Medicine:Prothrombin time|prothrombin time]], normal [[Medicine:Thrombin time|thrombin time]], but prolonged [[Medicine:Partial thromboplastin time|partial thromboplastin time]]. [[Medicine:Internal bleeding|Internal bleeding]] is common in people with severe haemophilia and some individuals with moderate haemophilia. The most characteristic type of internal bleed is a [[Medicine:Hemarthrosis|joint bleed]] where blood enters into the [[Biology:Joint|joint spaces]].<ref name=emed/> This is most common with severe haemophiliacs and can occur spontaneously (without evident trauma). If not treated promptly, joint bleeds can lead to permanent joint damage and disfigurement.<ref name=emed/> Bleeding into soft tissues such as [[Biology:Muscle|muscle]]s and [[Biology:Subcutaneous tissue|subcutaneous tissue]]s is less severe but can lead to damage and requires treatment.<ref>[https://www.medicalnewstoday.com/articles/321996 Medical News Today]</ref>
Children with mild to moderate haemophilia may not have any signs or symptoms at birth, especially if they do not undergo circumcision. Their first symptoms are often frequent and large [[Medicine:Bruise|bruise]]s and haematomas from frequent bumps and falls as they learn to walk. Swelling and bruising from bleeding in the joints, [[Physics:Soft tissue|soft tissue]], and muscles may also occur. Children with mild haemophilia may not have noticeable symptoms for many years. Often, the first sign in very mild haemophiliacs is heavy bleeding from a [[Medicine:Dentistry|dental procedure]], an accident, or [[Medicine:Surgery|surgery]]. Females who are carriers usually have enough clotting factors from their one normal gene to prevent serious bleeding problems, though some may present as mild haemophiliacs.{{citation needed|date=September 2021}}

===Complications===
Severe complications are much more common in cases of severe and moderate haemophilia. Complications may arise from the disease itself or from its treatment:<ref>[http://www.mayoclinic.com/health/hemophilia/DS00218/DSECTION=complications Hemophilia Complications] {{webarchive|url=https://web.archive.org/web/20100121052533/http://www.mayoclinic.com/health/hemophilia/DS00218/DSECTION%3Dcomplications |date=2010-01-21 }} Mayo Clinic Staff. 16 May 2009</ref>
* '''Deep internal bleeding''', e.g. deep-muscle bleeding, leading to swelling, numbness or pain of a limb.
* '''Joint damage''' from [[Medicine:Hemarthrosis|haemarthrosis]] (haemophilic arthropathy), potentially with severe pain, disfigurement, and even destruction of the joint and development of debilitating [[Medicine:Arthritis|arthritis]].
* '''[[Medicine:Transfusion transmitted infection|Transfusion transmitted infection]]''' from blood transfusions that are given as treatment.
* '''Adverse reactions''' to clotting factor treatment, including the development of an immune inhibitor which renders factor replacement less effective.
* '''[[Medicine:Intracranial hemorrhage|Intracranial haemorrhage]]''' is a serious medical emergency caused by the buildup of pressure inside the skull. It can cause disorientation, nausea, loss of consciousness, [[Medicine:Brain damage|brain damage]], and [[Biology:Death|death]].
Haemophilic arthropathy is characterized by chronic proliferative synovitis and cartilage destruction.<ref>{{cite journal|last=Rodriguez-Merchan|first=E. Carlos|title=Musculoskeletal Complications of Hemophilia|pmc=2821487|pmid=19921342|doi=10.1007/s11420-009-9140-9|volume=6|issue=1|year=2010|journal=HSS J|pages=37–42}}</ref> If an intra-articular bleed is not drained early, it may cause apoptosis of chondrocytes and affect the synthesis of proteoglycans. The hypertrophied and fragile synovial lining while attempting to eliminate excessive blood may be more likely to easily rebleed, leading to a vicious cycle of hemarthrosis-synovitis-hemarthrosis.  In addition, iron deposition in the synovium may induce an inflammatory response activating the immune system and stimulating angiogenesis, resulting in  cartilage and bone destruction.<ref name="pmid17822515">{{cite journal | vauthors = Valentino LA, Hakobyan N, Rodriguez N, Hoots WK | title = Pathogenesis of haemophilic synovitis: experimental studies on blood-induced joint damage | journal = Haemophilia | volume = 13 | pages = 10–3 | date = November 2007 | issue = Suppl 3 | pmid = 17822515 | doi = 10.1111/j.1365-2516.2007.01534.x | s2cid = 35723479 }}</ref>

==Genetics==
[[File:X-linked recessive (2).svg|thumb|upright=1.85|[[Biology:X-linked recessive inheritance|X-linked recessive inheritance]]]]

Typically, females possess two X-chromosomes, and males have one X and one [[Biology:Y chromosome|Y-chromosome]]. Since the mutations causing the disease are [[Biology:X-linked recessive inheritance|X-linked recessive]], a female carrying the defect on one of her X-chromosomes may not be affected by it, as the equivalent dominant [[Biology:Allele|allele]] on her other chromosome should express itself to produce the necessary clotting factors, due to X inactivation. Therefore, heterozygous females are just [[Biology:Genetic carrier|carriers]] of this genetic disposition. However, the Y-chromosome in the male has no gene for factors VIII or IX. If the genes responsible for production of factor VIII or factor IX present on a male's X-chromosome are deficient there is no equivalent on the Y-chromosome to cancel it out, so the deficient gene is not masked and the disorder will develop.<ref>{{Cite web|title=Hemophilia|url=https://www.genome.gov/genetics-glossary/hemophilia|access-date=2022-01-21|website=Genome.gov|language=en}}</ref>

Since a male receives his single X-chromosome from his mother, the son of a healthy female silently carrying the deficient gene will have a 50% chance of inheriting that gene from her and with it the disease; and if his mother is affected with haemophilia, he will have a 100% chance of being a haemophiliac. In contrast, for a female to inherit the disease, she must receive two deficient X-chromosomes, one from her mother and the other from her father (who must therefore be a haemophiliac himself). Hence, haemophilia is expressed far more commonly among males than females, while females, who must have two deficient X-chromosomes in order to have haemophilia, are far more likely to be silent carriers, survive childhood and to submit each of her genetic children to an at least 50% risk of receiving the deficient gene. However, it is possible for female carriers to become mild haemophiliacs due to lyonisation (inactivation) of the X-chromosomes. Haemophiliac daughters are more common than they once were, as improved treatments for the disease have allowed more haemophiliac males to survive to adulthood and become parents. Adult females may experience menorrhagia (heavy periods) due to the bleeding tendency. The pattern of inheritance is criss-cross type. This type of pattern is also seen in colour blindness.{{citation needed|date=September 2021}}

A mother who is a [[Biology:Genetic carrier|carrier]] has a 50% chance of passing the faulty X-chromosome to her daughter, while an affected father will always pass on the affected gene to his daughters. A son cannot inherit the defective gene from his father. [[Medicine:Genetic testing|Genetic testing]] and genetic counselling is recommended for families with haemophilia. Prenatal testing, such as amniocentesis, is available to pregnant women who may be carriers of the condition.<ref>{{Cite web|last=Naqvi|first=Erum|title=Hemophilia and Pregnancy - Hemophilia News Today|url=https://hemophilianewstoday.com/women-with-hemophilia__trashed/pregnancy-and-hemophilia/|access-date=2021-10-02|language=en-US}}</ref>

As with all genetic disorders, it is also possible for a human to acquire it spontaneously through [[Biology:Mutation|mutation]], rather than inheriting it, because of a new mutation in one of their parents' gametes. Spontaneous mutations account for about 33% of all cases of haemophilia A.<ref>{{cite book |last1=Kumar |first1=Parveen |last2=Clark |first2=Michael |title=Kumar & Clark's Clinical Medicine |year=2009 |publisher=Saunders Elsevier |isbn=9780702029936 |edition=7th}}</ref> About 30% of cases of haemophilia B are the result of a spontaneous gene mutation.

If a female gives birth to a haemophiliac son, either the female is a carrier for the blood disorder or the haemophilia was the result of a spontaneous mutation.<ref>{{Cite web |last=CDC |date=2019-04-19 |title=Information for Women {{!}} Hemophilia {{!}} NCBDDD {{!}} CDC |url=https://www.cdc.gov/ncbddd/hemophilia/women.html |access-date=2022-05-16 |website=Centers for Disease Control and Prevention |language=en-us}}</ref> Until modern direct DNA testing, however, it was impossible to determine if a female with only healthy children was a carrier or not.<ref>{{Cite journal |last1=Oldenburg |first1=Johannes |last2=Pezeshkpoor |first2=Behnaz |last3=Pavlova |first3=Anna |date=November 2014 |title=Historical review on genetic analysis in hemophilia A |url=https://pubmed.ncbi.nlm.nih.gov/25377322/ |journal=Seminars in Thrombosis and Hemostasis |volume=40 |issue=8 |pages=895–902 |doi=10.1055/s-0034-1395161 |issn=1098-9064 |pmid=25377322|s2cid=23864314 }}</ref>

If a male has the disease and has children with a female who is not a carrier, his daughters will be carriers of haemophilia. His sons, however, will not be affected with the disease. The disease is X-linked and the father cannot pass haemophilia through the Y-chromosome. Males with the disorder are then no more likely to pass on the gene to their children than carrier females, though all daughters they sire will be carriers and all sons they father will not have haemophilia (unless the mother is a carrier)<ref>{{Cite web |last=CDC |date=2022-08-01 |title=How Hemophilia is Inherited {{!}} Hemophilia {{!}} NCBDDD {{!}} CDC |url=https://www.cdc.gov/ncbddd/hemophilia/inheritance-pattern.html |access-date=2022-12-19 |website=Centers for Disease Control and Prevention |language=en-us}}</ref>

===Severity===
There are numerous different mutations which cause each type of haemophilia. Due to differences in changes to the genes involved, people with haemophilia often have some level of active clotting factor. Individuals with less than 1% active factor are classified as having severe haemophilia, those with 1–5% active factor have moderate haemophilia, and those with mild haemophilia have between 5% and 40% of normal levels of active clotting factor.<ref name=emed/>

==Diagnosis==
Haemophilia can be diagnosed before, during or after birth if there is a family history of the condition. Several options are available to parents. If there is no family history of haemophilia, it is usually only diagnosed when a child begins to walk or crawl. Affected children may experience joint bleeds or easy bruising.<ref name=":0">{{Cite web|url=http://www.nhs.uk/Conditions/Haemophilia/Pages/Diagnosis.aspx|title=Haemophilia - Diagnosis - NHS Choices|last=Choices|first=NHS|website=www.nhs.uk|access-date=2017-01-01|url-status=live|archive-url=https://web.archive.org/web/20170101162311/http://www.nhs.uk/Conditions/Haemophilia/Pages/Diagnosis.aspx|archive-date=2017-01-01}}</ref>

Mild haemophilia may only be discovered later, usually after an injury or a dental or surgical procedure.{{citation needed|date=September 2021}}

=== Before pregnancy ===
Genetic testing and counselling are available to help determine the risk of passing the condition onto a child.<ref name=":0" /> This may involve testing a sample of tissue or blood to look for signs of the genetic mutation that causes haemophilia.<ref name=":0" />

=== During pregnancy ===
A pregnant woman with a history of haemophilia in her family can test for the haemophilia gene. Such tests include:
* chorionic villus sampling (CVS): a small sample of the placenta is removed from the womb and tested for the haemophilia gene, usually during weeks 11–14 of pregnancy<ref>{{Cite web |title=Chorionic villus sampling |url=http://www.nhs.uk/conditions/chorionic-villus-sampling/pages/introduction.aspx |publisher=National Health Service |date=20 July 2018 |access-date=10 February 2020}}</ref>
* amniocentesis: a sample of amniotic fluid is taken for testing, usually during weeks 15–20 of pregnancy<ref>{{Cite web |title=Amniocentesis  |url=http://www.nhs.uk/conditions/amniocentesis/pages/introduction.aspx |publisher=National Health Service |date=17 April 2019 |access-date=10 February 2020}}</ref>

There is a small risk of these procedures causing problems such as miscarriage or premature labour, so the woman may discuss this with the doctor in charge of her care.<ref name=":0" />

=== After birth ===
If haemophilia is suspected after a child has been born, a blood test can usually confirm the diagnosis. Blood from the umbilical cord can be tested at birth if there's a family history of haemophilia. A [[Medicine:Blood test|blood test]] will also be able to identify whether a child has haemophilia A or B, and how severe it is.<ref name=":0" />

===Classification===
There are several types of haemophilia: haemophilia A, haemophilia B, haemophilia C, ''parahaemophilia'', ''acquired haemophilia A'', and ''acquired haemophilia B''.<ref>{{cite web|title=What Is Hemophilia? - NHLBI, NIH|url=http://www.nhlbi.nih.gov/health/health-topics/topics/hemophilia|website=www.nhlbi.nih.gov|access-date=21 June 2016|url-status=live|archive-url=https://web.archive.org/web/20160702224149/http://www.nhlbi.nih.gov/health/health-topics/topics/hemophilia/|archive-date=2 July 2016}}</ref><ref name="nlm.nih.gov">{{Cite web|url=https://www.nlm.nih.gov/medlineplus/ency/article/000538.htm|title=Hemophilia A: MedlinePlus Medical Encyclopedia|website=www.nlm.nih.gov|access-date=2016-06-21|url-status=live|archive-url=https://web.archive.org/web/20160705052319/https://www.nlm.nih.gov/medlineplus/ency/article/000538.htm|archive-date=2016-07-05}}</ref><ref name="eMed HemC"/><ref>{{Cite journal|last1=Páramo|first1=Laura|last2=Enciso Olivera|first2=Leonardo Jose|last3=Noreña|first3=Ivan|last4=Amaya|first4=María A.|last5=Santacruz|first5=Juan C.|date=2019-03-05|title=First Case of Acquired Hemophilia B in a Patient with HIV Infection: Case Report and Literature Review|journal=Cureus|volume=11|issue=3|pages=e4179|doi=10.7759/cureus.4179|doi-access=free |issn=2168-8184|pmc=6504016|pmid=31106079}}</ref>

Haemophilia A is a recessive X-linked genetic disorder resulting in a deficiency of functional clotting Factor VIII.<ref name="nlm.nih.gov"/> Haemophilia B is also a recessive X-linked genetic disorder involving a lack of functional clotting Factor IX.<ref>{{Cite web|url=https://www.nlm.nih.gov/medlineplus/ency/article/000539.htm|title=Hemophilia B: MedlinePlus Medical Encyclopedia|website=www.nlm.nih.gov|access-date=2016-06-21|url-status=live|archive-url=https://web.archive.org/web/20160705122431/https://www.nlm.nih.gov/medlineplus/ency/article/000539.htm|archive-date=2016-07-05}}</ref> Haemophilia C is an [[Biology:Autosome|autosomal]] genetic disorder involving a lack of functional clotting [[Biology:Factor XI|Factor XI]]. Haemophilia C is not completely recessive, as heterozygous individuals also show increased bleeding.<ref name="eMed HemC">Prasad Mathew, MBBS, DCH, [http://www.emedicine.com/ped/topic964.htm eMedicine - Hemophilia C] {{webarchive|url=https://web.archive.org/web/20081202194619/http://www.emedicine.com/ped/TOPIC964.HTM |date=2008-12-02 }}</ref>

The type of haemophilia known as ''parahaemophilia'' is a mild and rare form and is due to a deficiency in factor V. This type can be inherited or [[Biology:Acquired characteristic|acquired]].<ref name=Thal2013/>

A non-genetic form of haemophilia is caused by [[Biology:Autoantibody|autoantibodies]] against factor VIII and so is known as ''acquired haemophilia A''.<ref name=Mul2014/> It is a rare but potentially life-threatening bleeding disorder caused by the development of autoantibodies (inhibitors) directed against plasma coagulation factors.<ref>Tribuzi, Susanna, Naccarato, Alessia, Pelagalli, Lorella, et al.  Acquired Hemophilia A After Hepatic Yttrium-90 Radioembolization:  A Case Report.   ''A&A Case Reports.'' 2017;9(12):344-345.  doi:10.1213/XAA.0000000000000611.</ref> Acquired haemophilia can be associated with cancers, autoimmune disorders and following childbirth.<ref>{{cite journal|last1=Franchini|first1=M|last2=Mannucci|first2=PM|title=Acquired haemophilia A: a 2013 update.|journal=Thrombosis and Haemostasis|date=December 2013|volume=110|issue=6|pages=1114–20|pmid=24008306|doi=10.1160/TH13-05-0363|citeseerx=10.1.1.684.7962|s2cid=2174637}}</ref>

==Management==
There is no long-term cure. Treatment and prevention of bleeding episodes is done primarily by replacing the missing blood clotting factors.<ref name=CDC2014/>

===Clotting factors===
[[File:Factor VIII concentrate in Commercial Packaging.JPG|thumb|Commercially produced factor concentrates such as "Advate", a recombinant Factor VIII, come as a white powder in a vial which must be mixed with sterile water prior to intravenous injection.]]
Clotting factors are usually not needed in mild haemophilia.<ref name=NIH2013Tx/> In moderate haemophilia clotting factors are typically only needed when bleeding occurs or to prevent bleeding with certain events.<ref name=NIH2013Tx/> In severe haemophilia [[Medicine:Preventive healthcare|preventive use]] is often recommended two or three times a week and may continue for life.<ref name=NIH2013Tx/> Rapid treatment of bleeding episodes decreases damage to the body.<ref name=NIH2013Tx/>

Factor VIII is used in haemophilia A and factor IX in haemophilia B. Factor replacement can be either isolated from human blood serum, [[Biology:Recombinant DNA|recombinant]], or a combination of the two. Some people develop [[Biology:Antibodies|antibodies]] (inhibitors) against the replacement factors given to them, so the amount of the factor has to be increased or non-human replacement products must be given, such as porcine factor VIII.<ref>{{Cite journal|last1=Mannucci|first1=Pier Mannuccio|last2=Franchini|first2=Massimo|date=2017|title=Porcine recombinant factor VIII: an additional weapon to handle anti-factor VIII antibodies|journal=Blood Transfusion|volume=15|issue=4|pages=365–368|doi=10.2450/2016.0030-16|issn=1723-2007|pmc=5490733|pmid=27483484}}</ref>

If a person becomes refractory to replacement coagulation factor as a result of high levels of circulating inhibitors, this may be partially overcome with recombinant human [[Biology:Factor VIII|factor VIII]].<ref>{{Cite journal|last1=Witmer|first1=Char|last2=Young|first2=Guy|date=2013|title=Factor VIII inhibitors in hemophilia A: rationale and latest evidence|journal=Therapeutic Advances in Hematology|volume=4|issue=1|pages=59–72|doi=10.1177/2040620712464509|issn=2040-6207|pmc=3629762|pmid=23610614}}</ref>

In early 2008, the US [[Organization:Food and Drug Administration|Food and Drug Administration]] (FDA) approved an anti-haemophilic drug completely free of albumin, which made it the first anti-haemophilic drug in the US to use an entirely synthetic purification process.<ref>{{Cite web|date=2008-02-22|title=FDA Gives the Go-Ahead to Wyeth for Hemophilia A Therapy and Abbott for JIA Drug|url=https://www.genengnews.com/news/fda-gives-the-go-ahead-to-wyeth-for-hemophilia-a-therapy-and-abbott-for-jia-drug/|access-date=2021-02-10|website=GEN - Genetic Engineering and Biotechnology News|language=en-US}}</ref> Since 1993 recombinant factor products (which are typically cultured in [[Biology:Chinese hamster ovary cell|Chinese hamster ovary]] (CHO) tissue culture cells and involve little, if any human plasma products) have been available and have been widely used in wealthier western countries. While recombinant clotting factor products offer higher purity and safety, they are, like concentrate, extremely expensive, and not generally available in the developing world. In many cases, factor products of any sort are difficult to obtain in developing countries.{{Citation needed|date=August 2012}}

Clotting factors are either given preventively or on-demand. Preventive use involves the infusion of clotting factor on a regular schedule in order to keep clotting levels sufficiently high to prevent spontaneous bleeding episodes. On-demand (or episodic) treatment involves treating bleeding episodes once they arise. In 2007, a trial comparing on-demand treatment of boys (< 30 months) with haemophilia A with [[Medicine:Preventive healthcare|prophylactic treatment]] (infusions of 25 IU/kg body weight of Factor VIII every other day) in respect to its effect on the prevention of joint-diseases. When the boys reached 6 years of age, 93% of those in the prophylaxis group and 55% of those in the episodic-therapy group had a normal index joint-structure on MRI.<ref name="pmid17687129">{{cite journal |vauthors=Manco-Johnson MJ, Abshire TC, Shapiro AD, Riske B, Hacker MR, Kilcoyne R, Ingram JD, Manco-Johnson ML, Funk S, Jacobson L, Valentino LA, Hoots WK, Buchanan GR, DiMichele D, Recht M, Brown D, Leissinger C, Bleak S, Cohen A, Mathew P, Matsunaga A, Medeiros D, Nugent D, Thomas GA, Thompson AA, McRedmond K, Soucie JM, Austin H, Evatt BL | title = Prophylaxis versus episodic treatment to prevent joint disease in boys with severe hemophilia | journal = N. Engl. J. Med. | volume = 357 | issue = 6 | pages = 535–544 | year = 2007 | pmid = 17687129 | doi = 10.1056/NEJMoa067659 | doi-access = free }}</ref> Preventative treatment, however, resulted in average costs of {{wipe|United States dollar}}300,000 per year. The author of an editorial published in the same issue of the ''NEJM'' supports the idea that prophylactic treatment not only is more effective than on demand treatment but also suggests that starting after the first serious joint-related haemorrhage may be more cost effective than waiting until the fixed age to begin.<ref>{{cite journal | vauthors = Roosendaal G, Lafeber F | title = Prophylactic treatment for prevention of joint disease in hemophilia—cost versus benefit | journal = N. Engl. J. Med. | volume = 357 | issue = 6 | pages = 603–605 | year = 2007 | pmid = 17687136 | doi = 10.1056/NEJMe078098 }}</ref> Most haemophiliacs in third world countries have limited or no access to commercial blood clotting factor products.<ref>{{Cite web|url=https://www.wfh.org/en/data-collection|title=Data Collection - WFH Annual Global Survey - World Federation of Hemophilia|website=www.wfh.org|access-date=2018-12-10|archive-date=2019-07-25|archive-url=https://web.archive.org/web/20190725232956/https://www.wfh.org/en/data-collection|url-status=dead}}</ref>

===Other===
[[Chemistry:Desmopressin|Desmopressin]] (DDAVP) may be used in those with mild haemophilia A.<ref name=NIH2013Tx/> [[Chemistry:Tranexamic acid|Tranexamic acid]] or epsilon aminocaproic acid may be given along with clotting factors to prevent breakdown of clots.<ref name=NIH2013Tx/>

Pain medicines, [[Biology:Steroid|steroid]]s, and [[Medicine:Physical therapy|physical therapy]] may be used to reduce pain and swelling in an affected joint.<ref name=NIH2013Tx/> In those with severe hemophilia A already receiving FVIII, [[Chemistry:Emicizumab|emicizumab]] may provide some benefit.<ref>{{Cite web|url=https://www.fda.gov/Drugs/InformationOnDrugs/ApprovedDrugs/ucm622564.htm|title=Approved Drugs - FDA approves emicizumab-kxwh for hemophilia A with or without factor VIII inhibitors|last=Research|first=Center for Drug Evaluation and|website=www.fda.gov|access-date=2018-12-10}}</ref> Different treatments are used to help those with an acquired form of hemophilia in addition to the normal clotting factors. Often the most effective treatment is corticosteroids which remove the auto-antibodies in half of people. As a secondary route of treatment, cyclophosphamide and cyclosporine are used and are proven effective for those who did not respond to the steroid treatments. In rare cases a third route or treatment is used, high doses of intravenous immunoglobulin or immunosorbent that works to help control bleeding instead of battling the auto-antibodies.<ref>{{Cite journal|last1=Boggio|first1=Lisa N.|last2=Green|first2=David|date=2001|title=Acquired Hemophilia|journal=Reviews in Clinical and Experimental Hematology|language=en|volume=5|issue=4|pages=389–404|doi=10.1046/j.1468-0734.2001.00049.x|pmid=11844135|issn=1468-0734}}</ref>

===Contraindications===
[[Medicine:Anticoagulant|Anticoagulant]]s such as [[Chemistry:Heparin|heparin]] and [[Chemistry:Warfarin|warfarin]] are [[Medicine:Contraindication|contraindicated]] for people with haemophilia as these can aggravate clotting difficulties. Also contraindicated are those drugs which have "blood thinning" side effects. For instance, medicines which contain [[Chemistry:Aspirin|aspirin]], [[Chemistry:Ibuprofen|ibuprofen]], or naproxen sodium should not be taken because they are well known to have the [[Medicine:Side effect|side effect]] of prolonged bleeding.<ref name=kids>[http://kidshealth.org/kid/health_problems/blood/hemophilia.html How to Deal with Hemophilia] {{webarchive|url=https://web.archive.org/web/20070214041108/http://www.kidshealth.org/kid/health_problems/blood/hemophilia.html |date=2007-02-14 }} Reviewed by: Larissa Hirsch, MD 2007. kidshealth.org by Nemours. Retrieved 23 January 2010.</ref>

Also contraindicated are activities with a high likelihood of trauma, such as motorcycling and skateboarding. Popular sports with very high rates of physical contact and injuries such as American football, hockey, boxing, wrestling, and rugby should be avoided by people with haemophilia.<ref name=kids/><ref>"[http://www.hemophilia.org/NHFWeb/MainPgs/MainNHF.aspx?menuid=38&contentid=27 Playing it Safe: Bleeding Disorders, Sports and Exercise] {{webarchive|url=https://web.archive.org/web/20100914231704/http://www.hemophilia.org/NHFWeb/MainPgs/MainNHF.aspx?menuid=38&contentid=27 |date=2010-09-14 }}". Booklet. National Hemophilia Foundation.</ref> Other active sports like soccer, baseball, and basketball also have a high rate of injuries, but have overall less contact and should be undertaken cautiously and only in consultation with a doctor.<ref name=kids/>

==Prognosis==
Like most aspects of the disorder, [[Biology:Life expectancy|life expectancy]] varies with severity and adequate treatment. People with severe haemophilia who do not receive adequate, modern treatment have greatly shortened lifespans and often do not reach maturity. Prior to the 1960s when effective treatment became available, average life expectancy was only 11 years.<ref name=emed>[http://emedicine.medscape.com/article/210104-overview Hemophilia Overview] {{webarchive|url=https://web.archive.org/web/20090927063244/http://emedicine.medscape.com/article/210104-overview |date=2009-09-27 }} eMedicine from webMD. Dimitrios P Agaliotis, MD, PhD, FACP, Robert A Zaiden, MD, Fellow, and Saduman Ozturk, PA-C. Updated: 24 November 2009.</ref> By the 1980s the life span of the average haemophiliac receiving appropriate treatment was 50–60 years.<ref name=emed/> Today with appropriate treatment, males with haemophilia typically have a near normal [[Philosophy:Quality of life|quality of life]] with an average lifespan approximately 10 years shorter than an unaffected male.<ref>[http://www.wfh.org/en/page.aspx?pid=637#Life_expectancy World Federation of Hemophilia] {{webarchive|url=https://web.archive.org/web/20140201162113/http://www.wfh.org/en/page.aspx?pid=637 |date=2014-02-01 }} Frequently Asked Questions. 2005</ref>

Since the 1980s the primary leading cause of death of people with severe haemophilia has shifted from [[Medicine:Bleeding|haemorrhage]] to HIV/AIDS acquired through treatment with contaminated blood products.<ref name=emed/> The second leading cause of death related to severe haemophilia complications is intracranial haemorrhage which today accounts for one third of all deaths of people with haemophilia. Two other major causes of death include [[Medicine:Hepatitis|hepatitis]] infections causing [[Medicine:Cirrhosis|cirrhosis]] and obstruction of air or blood flow due to soft tissue haemorrhage.<ref name=emed/>

==Epidemiology==
Haemophilia frequency is about 1 instance in every 10,000 births (or 1 in 5,000 male births) for haemophilia A and 1 in 50,000 births for haemophilia B.<ref name=WFH>World Federation of Hemophilia [http://www.wfh.org/index.asp?lang=EN&url=2/1/1_1_1_FAQ.htm Frequently Asked Questions About Hemophilia] {{webarchive|url=https://web.archive.org/web/20080612182033/http://www.wfh.org/index.asp?lang=EN&url=2%2F1%2F1_1_1_FAQ.htm |date=2008-06-12 }}</ref> About 18,000 people in the United States have haemophilia. Each year in the US, about 400 babies are born with the disorder. Haemophilia usually occurs in males and less often in females.<ref>{{cite web|url=https://www.nlm.nih.gov/medlineplus/hemophilia.html|title=U.S. National Library of Medicine|access-date=2 December 2007|url-status=live|archive-url=https://web.archive.org/web/20071012095806/http://www.nlm.nih.gov/medlineplus/hemophilia.html|archive-date=12 October 2007}}</ref> It is estimated that about 2,500 Canadians have haemophilia A, and about 500 Canadians have haemophilia B.<ref>Canadian Hemophilia Society [http://www.hemophilia.ca/en/10.php FAQ] {{webarchive|url=https://web.archive.org/web/20080213000435/http://www.hemophilia.ca/en/10.php |date=2008-02-13 }}</ref>

==History==
{{quote box
|quote= "About seventy or eighty years ago, a woman by name of Smith, settled in the vicinity of Plymouth, New Hampshire, and transmitted the following idiosyncrasy to her descendants. It is one, she observed, to which her family is unfortunately subject, and had been the source not only of great solicitude, but frequently the cause of death. If the least scratch is made on the skin of some of them, as mortal a hemorrhagy will eventually ensue as if the largest wound is inflicted. (…) So assured are the members of this family of the terrible consequences of the least wound, that they will not suffer themselves to be bled on any consideration, having lost a relation by not being able to stop the discharge occasioned by this operation."|source=John C. Otto, 1803<ref>{{cite web |url=http://www.genmedhist.info/articles-and-papers/ |title=Otto JC. The Medical Repository. 1803; Vol VI (1): 1-4 |publisher=Genmedhist.info |access-date=2013-11-21 |url-status=live |archive-url=https://web.archive.org/web/20140904144726/http://www.genmedhist.info/articles-and-papers/ |archive-date=2014-09-04 }}</ref>
| width = 25%
| align = right}}

===Scientific discovery===
The excessive bleeding was known to ancient people. The Talmud instructs that a boy must not be circumcised if he had two brothers who died due to complications arising from their circumcisions, and [[Biography:Maimonides|Maimonides]] says that this excluded paternal half-brothers.<ref>Mishne Torah, laws of circumcision, chapter 1 law 18. It explicitly talks about multiple boys who have the same mother, regardless of whether or not they also have the same father.</ref> This may have been due to a concern about hemophilia.<ref>Singer, Isidore; et al., eds. (1901–1906). "Morbidity". The Jewish Encyclopedia. New York: Funk & Wagnalls.</ref> The first medical professional to describe the disease was Arab surgeon Al-Zahrawi, also known as Abulcasis. In the tenth century he described families whose males died of bleeding after only minor traumas.<ref>{{cite web|url=http://library.med.utah.edu/WebPath/COW/COW175.html|title=Case of the Week 175|publisher=University of Utah Medical Library|archive-url=https://web.archive.org/web/20110519140955/http://library.med.utah.edu/WebPath/COW/COW175.html|archive-date=19 May 2011}}</ref> While many other such descriptive and practical references to the disease appear throughout historical writings, scientific analysis did not begin until the start of the nineteenth century.{{citation needed|date=September 2021}}

In 1803, John Conrad Otto, a Philadelphian physician, wrote an account about "a hemorrhagic disposition existing in certain families" in which he called the affected males "bleeders".<ref name=nilsson>{{cite journal | author = Nilsson IM | title = Haemophilia—then and now | journal = Sydsvenska Medicinhistoriska Sallskapets Arsskrift | volume = 31 | pages = 33–52 | year = 1994 | pmid = 11640407 }}</ref> He recognised that the disorder was hereditary and that it affected mostly males and was passed down by healthy females. His paper was the second paper to describe important characteristics of an X-linked genetic disorder (the first paper being a description of [[Medicine:Color blindness|colour blindness]] by John Dalton who studied his own family). Otto was able to trace the disease back to a woman who settled near Plymouth, New Hampshire, in 1720. The idea that affected males could pass the trait onto their unaffected daughters was not described until 1813 when John F. Hay, published an account in ''The New England Journal of Medicine''.<ref>[http://www.genmedhist.info/Articles%20and%20Papers/ DIGITISED EARLY PAPERS AND BOOKS ON HUMAN AND MEDICAL GENETICS] {{webarchive|url=https://web.archive.org/web/20110721202446/http://www.genmedhist.info/Articles%20and%20Papers/ |date=2011-07-21 }} Genetics and Medicine Historical Network, Cardiff University.</ref><ref>{{cite journal|author=Hay J|title=Account of a remarkable hæmorrhagic disposition, existing in many individuals of the same family |journal=N Engl J Med Surg|volume=2|issue=3 |pages=221–5|date=July 1813|doi=10.1056/NEJM181307010020302|pmid=30493599 |pmc=5581570 |url=https://zenodo.org/record/1620327 }}</ref>

In 1924, a Finnish doctor discovered a hereditary bleeding disorder similar to haemophilia localised in Åland, southwest of Finland.<ref>{{cite journal|title=Haemophilia Special Issue: von Willebrand's Disease: a Report from a Meeting in the Åland Islands|doi=10.1111/hae.2012.18.issue-s6|volume=18|journal=Haemophilia|year = 2012}}</ref> This bleeding disorder is called [[Biology:Von Willebrand factor#History|"Von Willebrand Disease"]].

The term "haemophilia" is derived from the term "haemorrhaphilia" which was used in a description of the condition written by Friedrich Hopff in 1828, while he was a student at the [[Organization:University of Zurich|University of Zurich]].<ref name=nilsson/><ref name="History">{{cite web|url=http://www.wfh.org/2/1/1_1_3_HistoryHemophilia.htm|title=The History of hemophilia|access-date=5 June 2009|url-status=dead|archive-url=https://web.archive.org/web/20090331042700/http://www.wfh.org/2/1/1_1_3_HistoryHemophilia.htm|archive-date=31 March 2009}}</ref> In 1937, Patek and Taylor, two doctors from Harvard, discovered anti-haemophilic globulin.<ref name=blood>[https://books.google.com/books?id=H85dwxYTKLwC&q=Judah+the+Patriarch+hemophilia+Talmud&pg=RA1-PA1195 Chapter 38 Coagulation Factors V and VIII by GC White and GE Gilbert] {{webarchive|url=https://web.archive.org/web/20170911010926/https://books.google.com/books?id=H85dwxYTKLwC&pg=RA1-PA1195 |date=2017-09-11 }} in ''Blood: principles and practice of hematology: 2nd edition''. 2003. Eds. Robert I. Handin, Samuel E. Lux, Thomas P. Stossel. {{ISBN|978-0-7817-1993-3}}.</ref> In 1947, Pavlosky, a doctor from Buenos Aires, found haemophilia A and haemophilia B to be separate diseases by doing a lab test. This test was done by transferring the blood of one haemophiliac to another haemophiliac. The fact that this corrected the clotting problem showed that there was more than one form of haemophilia.{{cn|date=July 2022}}

===European royalty===
{{main|History:Haemophilia in European royalty}}
[[File:Erbgang Bluterkrankheit.svg|thumb|upright=1.8|Haemophilia in European royalty]]
Haemophilia has featured prominently [[History:Haemophilia in European royalty|in European royalty]] and thus is sometimes known as 'the royal disease'. Queen Victoria passed the mutation for haemophilia B<ref>{{cite news|author=Michael Price|title=Case Closed: Famous Royals Suffered From Hemophilia|url=http://sciencenow.sciencemag.org/cgi/content/full/2009/1008/2|newspaper=ScienceNOW Daily News|publisher=AAAS|date=8 October 2009|access-date=9 October 2009|url-status=dead|archive-url=https://web.archive.org/web/20091012020300/http://sciencenow.sciencemag.org/cgi/content/full/2009/1008/2|archive-date=12 October 2009}}</ref><ref>{{cite journal|author=Evgeny I. Rogaev|title=Genotype Analysis Identifies the Cause of the 'Royal Disease'|journal=Science|volume=326|issue=5954|pages=817|date=8 October 2009|display-authors=0|doi=10.1126/science.1180660|pmid=19815722|bibcode=2009Sci...326..817R|s2cid=206522975|doi-access=free}}</ref> to her son Leopold and, through two of her daughters, Alice and Beatrice, to various royals across the continent, including the royal families of Spain, Germany, and Russia. In Russia, Tsarevich Alexei, the son and heir of Tsar Nicholas II, famously had haemophilia, which he had inherited from his mother, Empress Alexandra, one of Queen Victoria's granddaughters. The haemophilia of Alexei would result in the rise to prominence of the Russian mystic Grigori Rasputin, at the imperial court.<ref>{{cite book|last=Massie|first=Robert K.|title=Nicholas and Alexandra: The Classic Account of the Fall of the Romanov Dynasty
|publisher={{wipe|Random House}}|date=2011|page=532|isbn=978-0307788474}}</ref>

It was claimed that Rasputin was successful at treating Tsarevich Alexei's haemophilia. At the time, a common treatment administered by professional doctors was to use [[Chemistry:Aspirin|aspirin]], which worsened rather than lessened the problem. It is believed that, by simply advising against the medical treatment, Rasputin could bring visible and significant improvement to the condition of Tsarevich Alexei.<ref>{{cite book|last=Jeffreys|first=Diarmud|title=Aspirin: The Remarkable Story of a Wonder Drug|publisher=[[Company:Bloomsbury Publishing|Bloomsbury Publishing]]|date=2008|page=121|isbn=9781596918160}}</ref>

In Spain, Queen Victoria's youngest daughter, Princess Beatrice, had a daughter Victoria Eugenie of Battenberg, who later became Queen of Spain. Two of her sons were haemophiliacs and both died from minor car accidents. Her eldest son, Prince Alfonso of Spain, Prince of Asturias, died at the age of 31 from internal bleeding after his car hit a telephone booth.<ref>{{Cite web|title=Tragic Drama Under the Miami Moon|url=http://www.biscaynetimes.com/index.php?option=com_content&id=264:tragic-drama-under-the-miami-moon&Itemid=162|access-date=2020-06-24|website=www.biscaynetimes.com|archive-date=2020-06-25|archive-url=https://web.archive.org/web/20200625034408/http://www.biscaynetimes.com/index.php?option=com_content&id=264:tragic-drama-under-the-miami-moon&Itemid=162|url-status=dead}}</ref> Her youngest son, Infante Gonzalo, died at age 19 from abdominal bleeding following a minor car accident in which he and his sister hit a wall while avoiding a cyclist. Neither appeared injured or sought immediate medical care and Gonzalo died two days later from internal bleeding.<ref>{{Cite news|title=AUTO CRASH FATAL TO SPANISH PRINCE; Don Gonzalo, 19, Succumbs to Hemophilia After Collision in Austrian Village. INFANTA BEATRIZ DRIVING Swerved Car to Avoid Hitting Bicyclist -- Ex-King Present at Son's Bedside.| work=The New York Times |url=http://timesmachine.nytimes.com/timesmachine/1934/08/14/93638215.html?pageNumber=7|access-date=2020-06-24|language=en}}</ref>

===Treatment===
The method for the production of an antihaemophilic factor was discovered by Judith Graham Pool from [[Organization:Stanford University|Stanford University]] in 1964,<ref>{{Cite journal|last1=Pool|first1=Judith G.|last2=Hershgold|first2=Edwabd J.|last3=Pappenhagen|first3=Albert R.|date=July 1964|title=High-potency Antihæmophilic Factor Concentrate prepared from Cryoglobulin Precipitate|journal=Nature|volume=203|issue=4942|pages=312|doi=10.1038/203312a0|pmid=14201780|issn=0028-0836|bibcode=1964Natur.203..312P|s2cid=4243913|doi-access=free}}</ref> and approved for commercial use in 1971 in the United States under the name ''[[Medicine:Cryoprecipitate|Cryoprecipitated AHF]]''.<ref>{{Cite web|url=https://www.fda.gov/media/76356/download|title=Alphabetical List of Licensed Establishments Including Product Approval Dates as of 30-APR-2019|publisher=FDA}}</ref> Together with the development of a system for transportation and storage of human plasma in 1965, this was the first time an efficient treatment for haemophilia became available.<ref>{{Cite journal|last1=Pool|first1=Judith Graham|last2=Shannon|first2=Angela E.|date=1965-12-30|title=Production of High-Potency Concentrates of Antihemophilic Globulin in a Closed-Bag System: Assay in Vitro and in Vivo|journal=New England Journal of Medicine|volume=273|issue=27|pages=1443–1447|doi=10.1056/NEJM196512302732701|pmid=5852902|issn=0028-4793}}</ref>

===Blood contamination===
[[File:Ryan White.jpg|right|thumb|Ryan White was an American haemophiliac who became infected with HIV/AIDS through contaminated blood products.]]
Up until late 1985 many people with haemophilia received clotting factor products that posed a risk of [[Biology:HIV|HIV]] and [[Medicine:Hepatitis C|hepatitis C]] infection. The plasma used to create the products was not screened or tested, nor had most of the products been subject to any form of viral inactivation.{{cn|date=July 2022}}

Tens of thousands worldwide were infected as a result of contaminated factor products including more than 10,000 people in the United States,<ref name="pmid20697550">{{cite journal | vauthors = White GC | title = Hemophilia: an amazing 35-year journey from the depths of HIV to the threshold of cure | journal = Trans. Am. Clin. Climatol. Assoc. | volume = 121 | pages = 61–73; discussion 74–5 | date = 2010 | pmid = 20697550 | pmc = 2917149 }}</ref> 3,500 British, 1,400 Japanese,<ref>{{cite web|url=http://www.jcie.org/researchpdfs/JapanResponseAIDS/Japansurvey.pdf|title=Japan's Response ro the Spread of HIV/AIDS|publisher = Japan Center for International Exchange|year = 2004}}</ref> 700 Canadians,<ref>{{cite web|title=Commemoration of the Tainted Blood Tragedy - Canadian Hemophilia Society|url=http://www.hemophilia.ca/en/commemoration-of-the-tainted-blood-tragedy/|website=www.hemophilia.ca}}</ref> 250 Irish,<ref>{{cite web|title=Report of the Tribunal of Inquiry into the Infection with HIV and Hepatitis C of Persons with Haemophilia and Related Matters {{!}} Department of Health|url=http://health.gov.ie/blog/publications/report-of-the-tribunal-of-inquiry-into-the-infection-with-hiv-and-hepatitis-c-of-persons-with-haemophilia-and-related-matters/|website=health.gov.ie|date=30 September 2002 }}</ref> and 115 Iraqis.<ref>{{cite news|last1=Zielbauer|first1=Paul von|title=Iraqis Infected by H.I.V.-Tainted Blood Try New Tool: A Lawsuit|url=https://www.nytimes.com/2006/09/04/world/middleeast/04aids.html|newspaper=The New York Times|date=4 September 2006}}</ref>

Infection via the tainted factor products had mostly stopped by 1986 by which time viral inactivation methods had largely been put into place,<ref name="pmid3672104">{{cite journal | vauthors = Lowe GD | title = Haemophilia, blood products and HIV infection | journal = Scott Med J | volume = 32 | issue = 4 | pages = 109–11 | date = August 1987 | pmid = 3672104 | doi = 10.1177/003693308703200404| s2cid = 21773694 }}</ref> although some products were shown to still be dangerous in 1987.<ref>{{cite news|vauthors = Picard A|title=RCMP lay 32 charges in tainted-blood case|url=https://www.theglobeandmail.com/news/national/rcmp-lay-32-charges-in-tainted-blood-case/article25426655/|website = The Globe and Mail}}</ref>

==Research==

===Gene therapy===
In those with severe haemophilia, [[Biology:Gene therapy|gene therapy]] may reduce symptoms to those that a person with mild or moderate haemophilia might have.<ref name=Pey2016/> The best results have been found in haemophilia B.<ref name=Pey2016/> In 2016 early stage human research was ongoing with a few sites recruiting participants.<ref name=Pey2016/> In 2017 a gene therapy trial on nine people with haemophilia A reported that high doses did better than low doses.<ref name="pmid29224506">{{cite journal | vauthors = Rangarajan S, Walsh L, Lester W, Perry D, Madan B, Laffan M, Yu H, Vettermann C, Pierce GF, Wong WY, Pasi KJ | title = AAV5-Factor VIII Gene Transfer in Severe Hemophilia A | journal = N. Engl. J. Med. | volume = 377 | issue = 26 | pages = 2519–2530 | date = December 2017 | pmid = 29224506 | doi = 10.1056/NEJMoa1708483 | hdl = 10044/1/57163 | url = http://qmro.qmul.ac.uk/xmlui/handle/123456789/31880 | doi-access = free | hdl-access = free }}</ref><ref name="pmid29224412">{{cite journal | vauthors = van den Berg HM | title = A Cure for Hemophilia within Reach | journal = N. Engl. J. Med. | volume = 377 | issue = 26 | pages = 2592–2593 | date = December 2017 | pmid = 29224412 | doi = 10.1056/NEJMe1713888}}</ref> It is not currently an accepted treatment for haemophilia.<ref name=NIH2013Tx/>

In July 2022 results of a gene therapy candidate for haemophilia B called  FLT180 were announced, it works using an [[Biology:Adeno-associated virus|adeno-associated virus]] (AAV) to restore the clotting [[Biology:Factor IX|factor IX]] (FIX) protein, normal levels of the protein were observed with low doses of the therapy but immunosuppression was necessitated to decrease the risk of vector-related immune responses.<ref>{{Cite journal |last1=Chowdary |first1=Pratima |last2=Shapiro |first2=Susan |last3=Makris |first3=Mike |last4=Evans |first4=Gillian |last5=Boyce |first5=Sara |last6=Talks |first6=Kate |last7=Dolan |first7=Gerard |last8=Reiss |first8=Ulrike |last9=Phillips |first9=Mark |last10=Riddell |first10=Anne |last11=Peralta |first11=Maria R. |date=2022-07-21 |title=Phase 1–2 Trial of AAVS3 Gene Therapy in Patients with Hemophilia B |journal=New England Journal of Medicine |volume=387 |issue=3 |pages=237–247 |doi=10.1056/NEJMoa2119913 |pmid=35857660 |s2cid=250697905 |issn=0028-4793|doi-access=free }}</ref><ref>{{Cite web |title=Novel gene therapy could reduce bleeding risk for haemophilia patients |url=https://www.sciencedaily.com/releases/2022/07/220720193711.htm |access-date=2022-08-03 |website=ScienceDaily |language=en}}</ref><ref>{{Cite news |date=2022-07-21 |title=Transformational therapy cures haemophilia B |language=en-GB |work=BBC News |url=https://www.bbc.com/news/health-62240061 |access-date=2022-08-03}}</ref>

== See also ==
* [[Medicine:Coagulopathy|Coagulopathy]]
* Purpura secondary to clotting disorders
* [[Medicine:Von Willebrand disease|Von Willebrand disease]]
* [[Organization:World Federation of Hemophilia|World Federation of Hemophilia]]

==References==
{{Reflist}}

==External links==
* {{Curlie|Health/Conditions_and_Diseases/Blood_Disorders/Hemophilia/}}
* [https://wfh.org/ World Federation of Hemophilia]

{{Medical condition classification and resources
 | DiseasesDB = 5555
 | DiseasesDB_mult = {{DiseasesDB2|5561}} {{DiseasesDB2|29376}}
 | ICD11 = {{ICD11|3B10}}–{{ICD11|3B22}}
 | ICD10 = {{ICD10|D66}}–{{ICD10|D68}}
 | ICD9 = {{ICD9|286}}
 | ICDO = 0117
 | OMIM = 306700
 | OMIM_mult = {{OMIM|306900||none}} {{OMIM|264900||none}}
 | MedlinePlus = 000537
 | eMedicineSubj = med
 | eMedicineTopic = 3528
 | MeshID = D025861
 | Scholia = Q134003
}}
{{Diseases of megakaryocytes}}
{{Medicine}}

[[Category:Wikipedia medicine articles ready to translate]]

{{Sourceattribution|Haemophilia}}