HTC Network conducted a study using data collected during — on all male patients who visited federally supported U. The study aimed to. Prevalence is a statistical concept referring to the number of cases of a disease that are present in a particular population at a given time, whereas incidence refers to the number of new cases that develop in a given period of time.
More work is needed to get a better estimate of how many people living with hemophilia do not utilize HTCs for their care. It would also be important to know whether the health of this group differs from the health of people with hemophilia who are cared for in the HTCs.
Similar studies are needed to assess the size and characteristics of women with hemophilia A and B. For more information about Hemophilia, please visit our Hemophilia webpages.
Occurrence rates of haemophilia among males in the United States based on surveillance conducted in specialized haemophilia treatment centres. Haemophilia ; Skip directly to site content Skip directly to page options Skip directly to A-Z link. Usually the disease is inherited in an autosomal recessive manner, meaning that a person must inherit two defective gene copies to develop the condition.
However, in some cases, it also may be inherited in an autosomal dominant way, meaning that a single faulty copy of the gene is sufficient to trigger its onset.
In rare cases, this type of hemophilia also can be acquired instead of being inherited. In these cases, hemophilia C is normally associated with an underlying disorder, such as lupus.
Bleeds in this type of hemophilia tend to be milder and symptoms are not always related to FXI levels. Spontaneous and internal joint bleeds, which are common in other forms of hemophilia, usually do not occur in people with type C.
Treatment might consist of antifibrinolytics , such as aprotinin, which prevent blood clots from dissolving by slowing the breakdown of fibrin. Other treatments include fresh frozen plasma, or concentrated FXI. This last treatment, however, remains unavailable in the U. In rare instances, the immune system fails to recognize a clotting factor — usually FVIII — as a molecule that is part of the body. When that happens, the immune system starts producing antibodies that attack it as though it were a virus or other harmful foreign molecule, resulting in acquired hemophilia.
Although it usually affects the same clotting factor as hemophilia A, the bleeding patterns differ markedly between the two conditions. Why exactly this happens, however, is still not fully understood.
Bleeding in acquired hemophilia usually occurs just below the skin subcutaneous bleeds , in the muscles hematomas or bruises , and in the gastrointestinal tract. Joint bleeds are uncommon in acquired hemophilia, in contrast with hemophilia A. Bleeding often is severe in this type of hemophilia, and frequently spontaneous, meaning that it happens without a clear cause.
Acquired hemophilia affects males and females equally. The production of autoantibodies is sometimes associated with pregnancy, immune system disorders, cancer, or allergic reactions to certain drugs.
In about half of cases, the cause of acquired hemophilia is unknown. Hemophilia A and hemophilia B are inherited in an X-linked recessive pattern. The genes associated with these conditions are located on the X chromosome, which is one of the two sex chromosomes. In males who have only one X chromosome , one altered copy of the gene in each cell is sufficient to cause the condition. In females who have two X chromosomes , a mutation would have to occur in both copies of the gene to cause the disorder.
Because it is unlikely that females will have two altered copies of this gene, it is very rare for females to have hemophilia. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. In X-linked recessive inheritance, a female with one altered copy of the gene in each cell is called a carrier. Carrier females have about half the usual amount of coagulation factor VIII or coagulation factor IX, which is generally enough for normal blood clotting.
However, about 10 percent of carrier females have less than half the normal amount of one of these coagulation factors; these individuals are at risk for abnormal bleeding, particularly after an injury, surgery, or tooth extraction.
Genetics Home Reference has merged with MedlinePlus. Learn more. The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health. From Genetics Home Reference. Description Hemophilia is a bleeding disorder that slows the blood clotting process.
Frequency The two major forms of hemophilia occur much more commonly in males than in females. Causes Changes in the F8 gene are responsible for hemophilia A, while mutations in the F9 gene cause hemophilia B. Learn more about the genes associated with Hemophilia F8 F9.
0コメント