A medical condition in which the ability of the blood to clot is greatly reduced, causing the sufferer to bleed severely from even a slight injury. The condition is typically caused by a hereditary lack of a coagulation factor, most often factor VIII.
Definition
Amedical condition in which the ability of the blood to clot is severely reduced, causing the sufferer to bleed severely from even a slight injury.
The condition is typically caused by a hereditary lack of a coagulation factor, most often factor VIII.
Hemophilia is one of a group of inherited bleeding disorders that cause abnormal or exaggerated bleeding and poor blood clotting.Hemophilia A and B are inherited in an X-linked recessive genetic pattern, so males are commonly affected while females are usually carriers of the disease.
Hemophilia A is caused by a deficiency of clotting Factor VIII, while hemophilia B (also called Christmas disease) results from a deficiency of Factor IX
Variations
There are two main types of hemophilia: Hemophilia A (due to factor VIII deficiency) and Hemophilia B (due to factor IX deficiency). They are clinically almost identical and are associated with spontaneous bleeding into joints and muscles and internal or external bleeding after injury or surgery.
After repeated bleeding episodes permanent damage may be caused to the joints and muscles that have been affected, particularly the ankles, knees and elbows.
Approximately 1 in 5,000 males are born with Hemophilia A, and 1 in 30,000 males are born with Hemophilia B. Hemophilia affects people of all races and ethnic origins globally. The conditions are both X-linked and virtually all sufferers of hemophilia are males. Female carriers may also bleed abnormally, because some have low levels of the relevant clotting factor.
People with hemophilia have a genetic mutation in the affected gene on the X chromosome, which results in reduced production of Factor VIII or IX and creates a bleeding tendency, because coagulation takes much longer than normal, thus making the clot weak and unstable.
Approximately one third of patients with hemophilia have no family history of the disease, either because of new genetic mutations, or because previous affected generations either had daughters (who were carriers) or sons who died in early childhood from hemophilia or any other cause or who were not affected.
Acquired hemophilia: This is very rare. The patient develops the condition during his/her lifetime and it does not have a genetic or heritable cause. It occurs when the body forms antibodies that attack one or more blood clotting factors, (usually factor VIII), thus preventing the blood clotting mechanism from working properly. Patients may be male or female and the pattern of bleeding is rather different from that of classical hemophilia, the joints being rarely affected. The disorder is particularly associated with old age and occasionally complicates pregnancy.
Causes
Hemophiliais caused by a genetic mutation. The mutations involve genes that code for proteins that are essential in the blood clotting process. The bleeding symptoms arise because blood clotting is impaired.
The process of blood clotting involves a series of complex mechanisms involving 13 different proteins, classically termed factors I through XIII and written with Roman numerals. If the lining of the blood vessels becomes damaged, platelets are recruited to the injured area to form an initial plug. These activated platelets release chemicals that start the clotting cascade, activating the series of 13 proteins known as clotting factors. Ultimately, fibrin is formed, the protein that crosslinks with itself to form a mesh that makes up the final blood clot. The protein involved with hemophilia A is factor VIII (factor 8) and with hemophilia B is factor IX (factor 9).
Hemophilia A is caused by a mutation in the gene for factor VIII, so there is deficiency of this clotting factor. Hemophilia B (also called Christmas disease) results from a deficiency of factor IX due to a mutation in the corresponding gene.
A condition referred to as hemophilia C involves a deficiency of clotting factor XI. This condition is much rarer than hemophilia A and B and typically leads to mild symptoms. It is also not inherited in an X-linked manner and affects persons of both sexes.
Treatment
Hemophilia Acan be treatedwith a prescription hormone. This hormone is called desmopressin, which can be givenas an injection into your vein. This medication works by stimulating the factors responsible for the process of blood clotting.
Doctors can treat hemophilia B by infusing blood with donor clotting factors. Sometimes, the factors may be given in the synthetic form. These are called “recombinant clotting factors.”
Hemophilia C can be treated using plasma infusion. The infusion works to stop profuse bleeding. The deficient factor responsible for hemophilia C is only available as a medication in Europe.
Statistics in India
The best available prevalence data of hemophilia are from a global survey on hemophilia and bleeding disorders, conducted by the World Federation of Hemophilia (WFH), a global organization involved in promoting the care of people with hemophilia and bleeding disorders.This survey is conducted globally, and in 2011 included 108 countries and covered 90.6 per cent of the global population.
Indian data are reported by the HFI. The data showed that in 2011, India reported 14,718 patients with bleeding disorders and 11,586 patients with hemophilia A. India has a low prevalence of 0.7 per 1,00,000 population. The current case detection in India is 4.7 times lower to that of the USA. Adjusting the underdiagnosis of patients with hemophilia A in India to the prevalence rate of hemophilia A in the USA, the estimated number of patients in India would be around 54,454.
In case of hemophilia B, the prevalence rate of 0.1 per 1,00,000 population in India is 13 times lower to the prevalence rate of the USA (1.3 per 1,00,000). Adjusting for this difference in prevalence, there would be an estimated 21,931 patients with hemophilia B in the country (unpublished observation).