PBB Protein F8 image.jpg
A drawing of clotting factor VIII
SymptomsEasy and prolonged bleeding[1]
Usual onsetAt birth[2]
CausesUsually genetic[3]
Diagnostic methodBlood test[4]
PreventionPreimplantation screening[4]
TreatmentReplace missing blood clotting factors[3]
Frequency1 in 7,500 males (haemophilia A), 1 in 40,000 males (haemophilia B)[2][5]

Haemophilia is a mostly inherited genetic disorder that impairs the body's ability to make blood clots, a process needed to stop bleeding.[2][3] This results in people bleeding longer after an injury, easy bruising, and an increased risk of bleeding inside joints or the brain.[1] Those with a mild case of the disease may have symptoms only after an accident or during surgery.[1] Bleeding into a joint can result in permanent damage while bleeding in the brain can result in long term headaches, seizures, or a decreased level of consciousness.[1]

There are two main types of haemophilia: haemophilia A, which occurs due to not enough clotting factor VIII, and haemophilia B, which occurs due to not enough clotting factor IX.[2] They are typically inherited from one's parents through an X chromosome with a nonfunctional gene.[6] Rarely a new mutation may occur during early development or haemophilia may develop later in life due to antibodies forming against a clotting factor.[2][6] Other types include haemophilia C, which occurs due to not enough factor XI, and parahaemophilia, which occurs due to not enough factor V.[7][8] Acquired haemophilia is associated with cancers, autoimmune disorders, and pregnancy.[9][10] Diagnosis is by testing the blood for its ability to clot and its levels of clotting factors.[4]

Prevention may occur by removing an egg, fertilizing it, and testing the embryo before transferring it to the uterus.[4] Treatment is by replacing the missing blood clotting factors.[3] This may be done on a regular basis or during bleeding episodes.[3] Replacement may take place at home or in hospital.[11] The clotting factors are made either from human blood or by recombinant methods.[11] Up to 20% of people develop antibodies to the clotting factors which makes treatment more difficult.[3] The medication desmopressin may be used in those with mild haemophilia A.[11] Studies of gene therapy are in early human trials.[12]

Haemophilia A affects about 1 in 5,000–10,000, while haemophilia B affects about 1 in 40,000, males at birth.[2][5] As haemophilia A and B are both X-linked recessive disorders, females are rarely severely affected.[6] Some females with a nonfunctional gene on one of the X chromosomes may be mildly symptomatic.[6] Haemophilia C occurs equally in both sexes and is mostly found in Ashkenazi Jews.[5] In the 1800s haemophilia was common within the royal families of Europe.[5] The difference between haemophilia A and B was determined in 1952.[5] The word is from the Greek haima αἷμα meaning blood and philia φιλία meaning love.[13]

Signs and symptoms

Characteristic symptoms vary with severity. In general symptoms are internal or external bleeding episodes, which are called "bleeds".[14][15] People with more severe haemophilia suffer more severe and more frequent bleeds, while people with mild haemophilia usually suffer 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.[citation needed]

In both haemophilia A and B, there is spontaneous bleeding but a normal bleeding time, normal prothrombin time, normal thrombin time, but prolonged partial thromboplastin time. Internal bleeding is common in people with severe haemophilia and some individuals with moderate haemophilia. The most characteristic type of internal bleed is a joint bleed where blood enters into the joint spaces.[16] 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.[16] Bleeding into soft tissues such as muscles and subcutaneous tissues is less severe but can lead to damage and requires treatment.

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 bruises and haematomas from frequent bumps and falls as they learn to walk. Swelling and bruising from bleeding in the joints, 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 dental procedure, an accident, or 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.


Severe complications are much more common in cases of severe and moderate haemophilia. Complications may arise from the disease itself or from its treatment:[17]

  • Deep internal bleeding, e.g. deep-muscle bleeding, leading to swelling, numbness or pain of a limb.
  • Joint damage from haemarthrosis (haemophilic arthropathy), potentially with severe pain, disfigurement, and even destruction of the joint and development of debilitating arthritis.
  • 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.
  • Intracranial haemorrhage is a serious medical emergency caused by the buildup of pressure inside the skull. It can cause disorientation, nausea, loss of consciousness, brain damage, and death.

Haemophilic arthropathy is characterized by chronic proliferative synovitis and cartilage destruction.[18] 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.[19]

Other Languages
Afrikaans: Hemofilie
العربية: هيموفيليا
azərbaycanca: Hemofiliya
беларуская: Гемафілія
български: Хемофилия
bosanski: Hemofilija
català: Hemofília
čeština: Hemofilie
dansk: Hæmofili
Deutsch: Hämophilie
eesti: Hemofiilia
Ελληνικά: Αιμορροφιλία
español: Hemofilia
Esperanto: Hemofilio
euskara: Hemofilia
فارسی: هموفیلی
français: Hémophilie
Gaeilge: Haemaifilia
galego: Hemofilia
한국어: 혈우병
հայերեն: Հեմոֆիլիա
हिन्दी: हीमोफीलिया
hrvatski: Hemofilija
Bahasa Indonesia: Hemofilia
interlingua: Hemophilia
italiano: Emofilia
עברית: המופיליה
Basa Jawa: Hemofilia
ქართული: ჰემოფილია
қазақша: Гемофилия
Кыргызча: Гемофилия
latviešu: Hemofilija
lietuvių: Hemofilija
magyar: Hemofília
മലയാളം: ഹീമോഫീലിയ
Bahasa Melayu: Hemofilia
Nederlands: Hemofilie
नेपाली: हिमोफोलिया
日本語: 血友病
norsk: Hemofili
ਪੰਜਾਬੀ: ਹੀਮੋਫਿਲਿਆ
polski: Hemofilia
português: Hemofilia
română: Hemofilie
русский: Гемофилия
shqip: Hemofilia
Simple English: Haemophilia
slovenščina: Hemofilija
српски / srpski: Хемофилија
srpskohrvatski / српскохрватски: Hemofilija
Basa Sunda: Hémofilia
svenska: Hemofili
Türkçe: Hemofili
українська: Гемофілія
اردو: انس الدم
中文: 血友病