What is Haemophilia?
Haemophilia is a rare, inherited bleeding disorder in which the blood does not clot properly. In simple terms, this means that individuals with haemophilia bleed for a longer time than those without it, both externally from cuts and internally within the body. This abnormal clotting is due to a deficiency or absence of specific proteins in the blood called clotting factors.
The most appropriate description for haemophilia is an X-linked recessive genetic disorder. It is inherited through a mutation in a gene located on the X chromosome. This mode of inheritance is why haemophilia most often affects males. Females have two X chromosomes, and if one has the affected gene, the other can compensate, making them carriers who often have normal or near-normal factor levels. Males, with only one X and one Y chromosome, will develop haemophilia if their single X chromosome carries the mutation. It is important to note that while most cases are inherited, about one-third of diagnosed infants have no family history, meaning the mutation occurred spontaneously.
Types of Haemophilia and Severity
Haemophilia is classified into different types based on which clotting factor is missing. The two most common types are Haemophilia A and Haemophilia B.
- Haemophilia A (Classic Haemophilia): This is the most prevalent form, resulting from a deficiency of clotting factor VIII (8).
- Haemophilia B (Christmas Disease): This less common type is caused by a deficiency in clotting factor IX (9).
- Haemophilia C: A rarer, milder form involving factor XI (11) deficiency, which does not follow the X-linked inheritance pattern and can affect both males and females.
Disease severity is determined by the amount of active clotting factor in a person's blood:
- Mild Haemophilia: Factor levels are between 6% and 49% of normal. Bleeding usually only occurs after significant trauma or surgery and may not be noticed until adulthood.
- Moderate Haemophilia: Factor levels are between 1% and 5% of normal. Patients may experience bleeding episodes after injuries, dental work, or surgery, and occasionally, spontaneous bleeding.
- Severe Haemophilia: Factor levels are less than 1% of normal. Spontaneous bleeding episodes are frequent, often occurring into joints and muscles without a known cause.
Symptoms and Complications
The primary symptom of haemophilia is prolonged or uncontrollable bleeding. While small cuts are typically not an issue, internal bleeding is a major concern, particularly in severe cases.
Symptoms can include:
- Easy or large bruising (hematomas): Caused by bleeding under the skin.
- Bleeding into joints: A common form of internal bleeding, often affecting knees, elbows, and ankles. This causes pain, swelling, and can lead to permanent joint damage (hemophilic arthropathy) if untreated.
- Bleeding into muscles and soft tissue: Can lead to swelling, pain, and pressure on nerves.
- Spontaneous bleeding: Bleeding without apparent injury, especially in severe haemophilia.
- Other bleeding sites: Including the mouth and gums, nosebleeds, blood in the urine or stool, and prolonged bleeding after dental work, vaccinations, or surgery.
The most serious complications are life-threatening bleeds into vital organs like the brain, which can occur from even a simple head bump.
Diagnosis
Diagnosis often begins with a family history of bleeding disorders. For children with no known family history, diagnosis may follow an abnormal bleeding event, such as excessive bleeding after circumcision or severe bruising as they become mobile.
Diagnostic tests include:
- Screening tests: Such as the Activated Partial Thromboplastin Time (APTT) test, which measures how long it takes blood to clot and will be prolonged in haemophilia A and B.
- Clotting factor assays: These are specific tests that measure the level of clotting factor activity in the blood, confirming the type and severity of haemophilia.
- Genetic testing: Can be used to identify the specific gene mutation responsible for the disorder.
Treatment and Management
The main goal of haemophilia treatment is to replace the missing clotting factor.
- Factor Replacement Therapy: The standard treatment involves infusing (injecting into a vein) concentrated clotting factor products. These can be given on a regular schedule (prophylaxis) to prevent bleeds or as needed (episodic) to stop them. Modern factor products are either made from donated plasma (which is treated to kill viruses) or are genetically engineered (recombinant factor).
- Non-Factor Therapies: Newer treatments like emicizumab (Hemlibra®) function differently by mimicking the missing factor VIII, and are administered by injection under the skin.
- Gene Therapy: A revolutionary approach that has received recent FDA approval for certain forms of haemophilia. It involves delivering a working copy of the faulty gene into liver cells to allow the body to produce its own clotting factor.
- Desmopressin (DDAVP): A medication used for some individuals with mild Haemophilia A to stimulate the release of stored factor VIII.
- Clot-Preserving Medications (Antifibrinolytics): Used to help stabilize clots, especially for mouth bleeds.
Comparing Haemophilia and Von Willebrand Disease
Both haemophilia and Von Willebrand disease (vWD) are inherited bleeding disorders, but they differ in several key aspects.
| Feature | Haemophilia A and B | Von Willebrand Disease (vWD) |
|---|---|---|
| Cause | Deficiency in clotting factors VIII (A) or IX (B). | Deficiency or defect in von Willebrand factor (vWF). |
| Inheritance Pattern | Primarily X-linked recessive, affecting males more often. | Usually autosomal dominant, affecting males and females equally. |
| Prevalence | Less common; about 1 in 10,000 for Haemophilia A. | More common; up to 1-3% of the population have vWF abnormalities. |
| Bleeding Characteristics | More severe bleeding, often into joints and muscles; can be life-threatening. | Generally milder; presents as mucosal bleeding (nosebleeds, gum bleeds, heavy periods) and easy bruising. |
| Primary Treatment | Infusions of the missing clotting factor (VIII or IX). | Treatment varies but can involve DDAVP or vWF replacement therapies. |
Lifestyle and Support for Haemophilia Patients
With modern treatments, people with haemophilia can lead healthy and active lives. Management strategies include:
- Regular exercise: Activities like swimming and walking strengthen muscles and protect joints.
- Avoiding certain medications: Nonsteroidal anti-inflammatory drugs (NSAIDs) like aspirin and ibuprofen should be avoided as they can worsen bleeding.
- Excellent dental hygiene: Prevents gum disease and associated bleeding.
- Medical identification: Wearing a medical alert bracelet informs healthcare providers of the condition in an emergency.
- Working with a Comprehensive Treatment Center (HTC): Access to specialized hematologists, physical therapists, and social workers is crucial for comprehensive care and support.
Conclusion
In summary, the most appropriate description of haemophilia is an X-linked recessive genetic disorder that impairs the body's ability to clot blood due to a deficiency in specific clotting factors. While it presents significant health challenges, particularly from internal bleeding, advanced treatment options have transformed outcomes. Through regular prophylactic therapy, careful management, and access to comprehensive care, individuals with haemophilia can effectively control their condition and minimize complications, enabling them to lead fulfilling lives. Recent innovations in gene therapy offer hope for long-term solutions, further advancing the prospects for those living with this condition.
For more information on bleeding disorders and support resources, visit the CDC's page on Hemophilia.
