Hemophilia is an inherited genetic disorder that impairs the body’s ability to form blood clots, necessary to stop bleeding. Individuals with this condition bleed for a longer duration after an injury, experience easy bruising, and face an elevated risk of internal bleeding into joints or the brain. The severity of hemophilia depends on the amount of clotting factors present.
Understanding X-Linked Hemophilia
Hemophilia A and Hemophilia B are inherited through an X-linked recessive pattern, as the genes are on the X chromosome. Males have one X and one Y chromosome; if their single X chromosome carries the altered gene, they develop hemophilia. Females, with two X chromosomes, need both gene copies altered to develop the disorder, making severe hemophilia rare for them.
Carriers have enough normal clotting factor from their normal X chromosome to prevent severe bleeding, though some may experience milder symptoms like heavy menstrual bleeding or easy bruising. A mother who is a carrier has a 50% chance of passing the altered gene to each son, who would have hemophilia, and a 50% chance of passing it to each daughter, who would be a carrier.
Hemophilia A, also known as classic hemophilia, results from a deficiency in clotting Factor VIII. It is more common, affecting about 1 in 5,000 male births and accounting for 80% to 85% of all hemophilia cases. Hemophilia B, referred to as Christmas disease, is caused by a lack of clotting Factor IX. These factors are proteins that work with platelets to help blood form clots, a function disrupted when missing or in low amounts.
Recognizing Symptoms and Diagnosis
The symptoms of hemophilia vary in severity, depending on the level of clotting factor activity in the blood. Individuals with severe hemophilia, defined as less than 1% normal clotting factor activity, may experience frequent spontaneous bleeding episodes, often into their joints and muscles, even without injury. Those with moderate hemophilia (1% to 5% factor activity) bleed after injuries, while people with mild hemophilia (6% up to 49% factor activity) only bleed after significant injury, trauma, or surgery.
Common signs of hemophilia include easy bruising, prolonged bleeding after minor cuts or dental procedures, and nosebleeds. Internal bleeding into joints, known as hemarthrosis, is a serious symptom, causing pain, swelling, and reduced range of motion. Bleeding can occur in muscles or other internal organs, and in severe cases, bleeding into the brain can be life-threatening.
Diagnosis begins with a physical examination and a review of personal and family medical histories to identify abnormal bleeding patterns. Blood tests are then performed to measure blood clotting time and specific clotting factor levels. Tests include a complete blood count (CBC), prothrombin time (PT), and activated partial thromboplastin time (aPTT), followed by specific clotting factor assays to identify hemophilia type and severity.
Current Treatments and Management
The primary approach to treating hemophilia involves factor replacement therapy, infusing concentrated Factor VIII (for hemophilia A) or Factor IX (for hemophilia B) into the bloodstream. This therapy can be administered on-demand to stop bleeding episodes, or as prophylaxis, a regular infusion schedule preventing bleeds. Prophylactic treatment is recommended for individuals with severe hemophilia to maintain higher factor levels and reduce bleeding frequency and associated joint damage.
Factor concentrates used can be derived from human plasma or produced using recombinant technology. Recent advancements include extended half-life factor products, allowing less frequent infusions and improving convenience. These therapies aim to raise the circulating levels of the deficient clotting factor, allowing the blood to clot more effectively.
Beyond traditional factor replacement, newer non-factor replacement therapies have emerged. Emicizumab, a bispecific monoclonal antibody, mimics the function of Factor VIII by bridging Factor IX and Factor X to promote clot formation. This therapy is administered subcutaneously, offering a less burdensome alternative to intravenous infusions. Gene therapy holds promise as a long-term solution, aiming to introduce a functional copy of the deficient gene into the patient’s cells, enabling the body to produce the missing clotting factor.
Living with Hemophilia
Individuals with hemophilia can take steps to prevent bleeds and manage their condition. Avoiding medications that interfere with clotting, such as aspirin and non-steroidal anti-inflammatory drugs (NSAIDs), is important. Engaging in safe physical activities to minimize injury risk, like swimming or walking, while avoiding high-impact sports, helps reduce bleed frequency. Regular and thorough dental care is also advised to prevent gum bleeds and invasive dental procedures.
Despite preventive measures, acute bleeds can occur, and home management is important. Applying pressure and ice to external bleeds can help slow and stop bleeding. For internal bleeds, particularly into joints, recognizing symptoms like unusual sensations, swelling, or warmth is important for early intervention.
Wearing a medical alert bracelet or necklace is an effective way to inform emergency responders about their condition, type, and treatment factor, which is life-saving. Modern treatments have improved the outlook for individuals with hemophilia, allowing many to lead full, active lives. Continued research into gene therapy and other novel treatments contributes to an improved quality of life and increased life expectancy for those with this condition.