Summary about Disease
Christmas disease, also known as hemophilia B or Factor IX deficiency, is a genetic bleeding disorder caused by a deficiency or abnormality of clotting factor IX, a protein needed for normal blood clotting. This deficiency prevents blood from clotting properly, leading to prolonged or excessive bleeding, even from minor injuries. The severity of Christmas disease varies depending on the amount of factor IX present in the blood.
Symptoms
Symptoms vary depending on the severity of the factor IX deficiency. Common symptoms include:
Prolonged bleeding after injuries, surgery, dental procedures, or vaccinations.
Easy bruising.
Spontaneous bleeding into muscles and joints (hemarthrosis), causing pain, swelling, and stiffness.
Nosebleeds (epistaxis).
Blood in urine or stool (hematuria or melena).
Excessive bleeding after circumcision.
In infants, bleeding in the brain during or after birth (rare).
Causes
Christmas disease is caused by a genetic mutation in the F9 gene, which provides instructions for making factor IX. This gene is located on the X chromosome, meaning that males (who have one X and one Y chromosome) are more likely to be affected than females (who have two X chromosomes). Christmas disease is inherited in an X-linked recessive pattern.
Inheritance:
Males who inherit the mutated gene from their mother will have hemophilia B.
Females who inherit one copy of the mutated gene are typically carriers. They usually do not have symptoms but can pass the gene on to their children. A female carrier can have mild bleeding symptoms.
In rare cases, females can have hemophilia B if they inherit two copies of the mutated gene or if they have one copy and inactivation (lyonization) occurs disproportionately of the normal X chromosome.
Spontaneous mutations can also occur, meaning a person can have hemophilia B even without a family history of the condition.
Medicine Used
The primary treatment for Christmas disease involves replacing the missing or deficient factor IX. Treatment options include:
Factor IX replacement therapy: This involves infusing concentrated factor IX derived from human plasma (plasma-derived factor IX) or manufactured using recombinant DNA technology (recombinant factor IX).
Desmopressin (DDAVP): This medication can stimulate the release of factor VIII (another clotting factor) and von Willebrand factor, which can help improve clotting in mild cases of hemophilia B. It's usually not effective in moderate or severe cases.
Bypassing agents: These medications (e.g., activated prothrombin complex concentrate (aPCC) or recombinant factor VIIa) can be used to promote blood clotting when factor IX replacement therapy is not effective or when inhibitors (antibodies against factor IX) are present.
Gene therapy: Gene therapy introduces a functional copy of the F9 gene into the body, enabling the body to produce factor IX on its own. Gene therapy for Hemophilia B has been approved in some countries and represents an advance in care.
Is Communicable
No, Christmas disease (hemophilia B) is not communicable. It is a genetic disorder caused by a mutation in the F9 gene and cannot be spread from person to person through any infectious means.
Precautions
People with Christmas disease should take the following precautions to minimize the risk of bleeding:
Avoid activities that may cause injury: High-impact sports and activities with a high risk of trauma should be avoided.
Inform healthcare providers: Always inform doctors, dentists, and other healthcare providers about the diagnosis before any medical or dental procedures.
Medication awareness: Avoid medications that can increase the risk of bleeding, such as aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs). Use acetaminophen (Tylenol) for pain relief instead.
Regular factor IX infusions: Follow the prescribed schedule for factor IX replacement therapy to maintain adequate factor IX levels.
Prophylactic treatment: Prophylactic factor IX infusions (regular infusions to prevent bleeding) are often recommended, especially for children and those with severe hemophilia B.
Vaccinations: Get vaccinated against hepatitis A and B, as blood products used in treatment can carry a small risk of infection.
How long does an outbreak last?
Christmas disease isn't characterized by "outbreaks" in the typical sense of an infectious disease. Instead, bleeding episodes can occur.
Untreated Bleeding: Without treatment, a bleeding episode can last for days or even weeks, depending on the severity of the bleed and the location.
Treated Bleeding: With appropriate factor IX replacement therapy, most bleeding episodes can be effectively controlled within a few hours to a few days. The duration depends on how quickly treatment is initiated and the severity of the bleed. Prophylactic treatment aims to prevent these bleeding episodes altogether.
How is it diagnosed?
Diagnosis of Christmas disease involves the following:
Medical history and physical examination: Assessment of bleeding history, family history of bleeding disorders, and physical examination to identify signs of bleeding.
Blood tests:
Clotting factor assays: Measures the level of factor IX in the blood. A low level of factor IX indicates hemophilia B.
Partial thromboplastin time (PTT): A blood test that measures the time it takes for blood to clot. The PTT is usually prolonged in people with hemophilia B.
Prothrombin time (PT): A blood test that measures the time it takes for blood to clot. This is usually normal in people with hemophilia B.
Mixing studies: If the PTT is prolonged, mixing studies can help determine whether the prolongation is due to a factor deficiency or an inhibitor.
Genetic testing: Genetic testing of the F9 gene can confirm the diagnosis and identify the specific mutation causing the hemophilia. This can also be used for carrier testing in women with a family history of hemophilia.
Timeline of Symptoms
The onset and progression of symptoms vary depending on the severity of the hemophilia B.
Severe Hemophilia B: Symptoms often appear in infancy or early childhood. Spontaneous bleeding episodes into joints and muscles are common.
Moderate Hemophilia B: Symptoms may not be apparent until later in childhood or adolescence. Bleeding may occur after minor injuries or surgical procedures.
Mild Hemophilia B: Symptoms may be mild and only noticed after major surgery or trauma. Some individuals may not be diagnosed until adulthood.
Throughout life: The frequency and severity of bleeding episodes can vary over time, influenced by factors such as activity level, treatment adherence, and the presence of inhibitors.
Important Considerations
Inhibitors: Some people with hemophilia B can develop inhibitors (antibodies) against factor IX, which can make treatment less effective. Regular monitoring for inhibitors is important.
Joint damage: Repeated bleeding into joints can lead to chronic joint damage (hemophilic arthropathy), causing pain, stiffness, and disability. Early and aggressive treatment with factor IX replacement therapy can help prevent or minimize joint damage.
Psychosocial support: Living with a chronic bleeding disorder can be challenging. Psychosocial support and counseling can help individuals and families cope with the emotional and practical challenges of hemophilia B.
Comprehensive Care: People with hemophilia B benefit from comprehensive care at a hemophilia treatment center (HTC). HTCs provide multidisciplinary care, including hematologists, nurses, physical therapists, social workers, and other specialists.
Emergency preparedness: Individuals with hemophilia B should have a plan in place for managing bleeding emergencies, including access to factor IX concentrate and a contact list of healthcare providers.