Editing Haemophilia (section)

==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=NHS>{{Cite web|url=http://www.nhs.uk/Conditions/Haemophilia/Pages/Diagnosis.aspx|title=Haemophilia — Diagnosis |work=NHS Choices |publisher=UK National Health Service |access-date=1 January 2017|url-status=live|archive-url=https://web.archive.org/web/20170101162311/http://www.nhs.uk/Conditions/Haemophilia/Pages/Diagnosis.aspx|archive-date=1 January 2017}}</ref>

Mild haemophilia may only be discovered later, usually after an injury or a dental or surgical procedure.<ref>{{cite journal |vauthors=Alesci RS, Goldmann G, Halimeh S, Holstein K, Königs C, Miesbach W, Pfrepper C, Olivieri M |title=Patient perspective on living with mild hemophilia in Germany: results from a nationwide survey |journal=Front Med (Lausanne) |volume=11 |issue= |pages=1347024 |date=2024 |pmid=38379557 |doi=10.3389/fmed.2024.1347024 |pmc=10877726 |doi-access=free}}</ref>

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

=== 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=NHS />

=== 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 [[blood test]] will also be able to identify whether a child has haemophilia A or B, and how severe it is.<ref name=NHS />

===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=21 June 2016|url-status=live|archive-url=https://web.archive.org/web/20160705052319/https://www.nlm.nih.gov/medlineplus/ency/article/000538.htm|archive-date=5 July 2016}}</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=5 March 2019|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 |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>{{MedlinePlusEncyclopedia|000539|Hemophilia B}}</ref> Haemophilia C is an [[Autosome|autosomal]] genetic disorder involving a lack of functional clotting [[Factor XI]]. Haemophilia C is not completely recessive, as [[heterozygous]] individuals also show increased bleeding.<ref name="eMed HemC">{{EMedicine|article|955690|Hemophilia C}}</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 [[acquired characteristic|acquired]].<ref name=Thal2013/>

A non-genetic form of haemophilia is caused by [[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>{{cite journal |last1=Tribuzi |first1=Susanna |last2=Naccarato |first2=Alessia |last3=Pelagalli |first3=Lorella |display-authors=etal |title=Acquired Hemophilia A After Hepatic Yttrium-90 Radioembolization: A Case Report |journal=A&A Case Reports |volume=9 |issue=12 |pages=344–5 |date=2017 |doi=10.1213/XAA.0000000000000611 |pmid=28767473 }}</ref> Acquired haemophilia can be associated with cancers, autoimmune disorders and following childbirth.<ref name=Franchini13/>