Read this article to learn all about Haemophilia A, an inherited disease.
Figure 1: Visual Diagram of a healthy blood vessel vs. one with Hemophilia
General Information
Hemophilia A is an inherited disorder caused by a gene mutation of X-chromosome. The gene is responsible for the instructions for controlling blood clotting factors. Therefore mutation of X-chromosome causes a lack of factor VIII, which leads to blood being unable to clot properly. General symptoms of Hemophilia A include internal bleeding into joints (causing them to feel tight as they swell), prolonged bleeding after surgeries, easy brushing, and bleeding into muscles. In addition, prolonged, hard-to-stop bleeding can occur: in the mouth and gums, after receiving shots, and in recurring nosebleeds. Trauma and wounds to the brain are the most dangerous as internal bleeding is hard to treat and in severe cases, could lead to death.
Hemophilia A is most prevalent in males— 1/5000 males have it. Since males only have one X-chromosome, they are more likely to get the disorder if that gene had the disorder’s mutation. However, females with two X chromosomes are less likely to receive 2 mutated genes. As the mutated gene is recessive, the normal gene would produce enough Factor VIII for female carriers to live asymptomatic lives.
3 Main Types
Haemophilia A is broken down into 3 sub-categories based on the severity of the disorder (amount of factor VIII). Severe Hemophilia A occurs when there is less than 1% of factor VIII than an average person. People with severe Hemophilia A are diagnosed before they turn 2 years old as, without proper treatment, an average of 2-5 bleeding episodes in a month can occur. Approximately 60% of all Hemophilia A patients have severe Hemophilia A.
Moderate Haemophilia A occurs when only 1-5% of the normal clotting factor is present in the blood. Patients are usually diagnosed between 5-6 years old as bleeding episodes occur less frequently— once every month to a year.
Mild Haemophilia A is diagnosed when 5-30% of the clotting factor is present in the blood of the patient. Due to bleeding episodes only taking place once every 1 to 10 years, it takes a longer time to diagnose.
All patients with haemophilia A are at risk for excessive bleeding after complex surgeries and major trauma.
Testing
When testing for Hemophilia A, labs assess the amount of factor VIII and screening coagulation tests that record the amount of time for the blood to clot. In Hemophilia A, the activated partial thromboplastin time (aPTT) takes longer when there is 70% less factor VIII than the average amount.
Treatment
There is no cure for this disorder but prevention methods and treatments for the symptoms are provided. Treatments include injecting a shot of concentrations of Factor VIII and referral to Hemophilia Treatment Centers (HTC), which specialize in the disorder. The concentrate can be made through a lab or derived from frozen plasma of human blood donations. The latter method is risky as infections could be passed through the blood, causing the treatment to be less preferred by doctors. Patients can learn how to independently infuse Factor VIII concentrate by a drip, allowing them to perform it at home.
Inhibitors
Yet, 30% of patients with severe Hemophilia A develop inhibitors, antibodies against the concentrate. This means there is a need for more specialized treatments with more or a different clotting factor. These patients would also be unable to live a satisfactory life due to amplified joint pain. For now, the solution to the problem is to use Immune Tolerance Induction, decreasing the number of inhibitors. This works in 70% of cases and eventually, patients can switch back to a regular treatment plan.
Citations
[1] CDC. “What Is Hemophilia.” Centers for Disease Control and Prevention, U.S. Department of Health & Human Services, 17 July 2020, www.cdc.gov/ncbddd/hemophilia/facts.html.
[2] Europe PMC. “Europe PMC.” Europepmc.org, 2019, europepmc.org/article/nbk/nbk1404.
[3] NORD. “Hemophilia a - NORD (National Organization for Rare Disorders).” NORD (National Organization for Rare Disorders), NORD, 2015, rarediseases.org/rare-diseases/hemophilia-a/.
[4] Cleveland Clinic. “What Is Hemophilia a & Hemophilia B? | Cleveland Clinic: Health Library.” Cleveland Clinic, 2017, my.clevelandclinic.org/health/diseases/14083-hemophilia.
[5] Lambert, Catherine, et al. “Hemophilia Carrier’s Awareness, Diagnosis, and Management in Emerging Countries: A Cross-Sectional Study in Côte d’Ivoire (Ivory Coast).” Orphanet Journal of Rare Diseases, vol. 14, 1 Feb. 2019, www.ncbi.nlm.nih.gov/pmc/articles/PMC6359866/, 10.1186/s13023-019-1005-9. Accessed 16 Jan. 2021.
Comments