hemophilia A

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Related to haemophilia A: haemophilia B, Von Willebrand disease, Haemophilia C

hemophilia

 [he″mo-fil´e-ah]
a hereditary disorder characterized by a strong tendency to bleed. The most common types are carried as sex-linked genes with females carrying the trait and disease manifestations almost always in males. (Occasionally, women carrying the trait for hemophilia A or B have bleeding manifestations themselves, probably as a result of nonrandom inactivation of their X chromosomes and overexpression of the X chromosome coding for hemophilia; these women are referred to as symptomatic carriers.) All daughters of affected men will be carriers for the gene of hemophilia.

The two most common types are hemophilia A and hemophilia B. Over 80 per cent of patients have hemophilia A (classical hemophilia), which is characterized by a deficiency of coagulation factor VIII. Hemophilia B (called also Christmas disease) affects about 15 per cent of hemophiliacs and is characterized by a deficiency of coagulation factor IX. Other coagulation factor deficiencies are less common, with patients suffering either milder bleeding or thrombotic episodes.
Symptoms. Bleeding in hemophilic patients is variable, depending on the level of deficiency of the clotting factor. Approximately 60 per cent of persons with hemophilia A or B are severely affected and may have spontaneous bleeding without any recognized trauma. Soft tissue bleeding from the neck, lower face, and tongue may cause grave consequences if not treated. Hematuria and gastrointestinal bleeding are likely, and hemarthrosis (bleeding into joints) can lead to painful stiffening and permanent disability. The leading cause of death, however, is intracranial bleeding. Hemorrhagic complications can be avoided or minimized with early and adequate factor replacement therapy.

Hemophilia A is characterized by a factor VIII level of from 0 to 30 per cent of normal. The partial thromboplastin time (PTT) is usually prolonged. The platelet count, bleeding time, and prothrombin time (PT) are normal. In hemophilia B there is a low factor IX level and the prothrombin time is usually prolonged.
Treatment. The treatment of persons with hemophilia depends on the severity of their disease and the nature of a given bleeding episode. Several therapeutic materials are available for correction of the clotting defect in hemophilia A. Factor VIII is present in commercial lyophilized factor VIII concentrates, cryoprecipitate, fresh whole blood, and fresh frozen plasma. Purified factor VIII concentrate, however, is the treatment of choice. Successful treatment of those with mild hemophilia A can often be done with desmopressin (DDAVP). While factor IX is present in fresh frozen plasma, it is not concentrated in cryoprecipitate, so that the latter is not useful for treatment of hemophilia B. Factor IX is present in two commercially prepared concentrates, known as factor IX complex concentrates and coagulation factor IX concentrates.

All persons with hemophilia should be immunized with hepatitis B vaccine. Suspected bleeding into the central nervous system must be promptly treated; when this happens, consultation with or transfer to a Hemophilia Treatment Center is mandatory. Early treatment of hemarthroses is essential for maintenance of joint health; infusions administered within 4 to 6 hours of onset of symptoms are sufficient to stop bleeding and restore joint function. Medically supervised home infusion therapy has become an integral part of the comprehensive care of patients with bleeding disorders and has facilitated the treatment of bleeding episodes outside the hospital setting.
Patient Care. Advances in therapy have greatly improved the prognosis and management of hemophilia, but new issues have emerged, including the impact on immune status of purer factor concentrates, escalating financial considerations, and therapeutics for infections with hepatitis B, hepatitis C, and the human immunodeficiency virus. Multidisciplinary comprehensive care that incorporates patient and family educational strategies continues to be an essential element of care. Surgery and dental care require a team approach by individuals with specialized knowledge and expertise, in order to ensure favorable outcomes. A diagnosis of hemophilia presents many challenges, not the least of which are psychosocial issues.

Excellent sources of information for both professionals and nonprofessionals are the National Hemophilia Foundation, 110 Greene St., Suite 303, New York, NY 10012 (telephone 212-219-8180) and the Hemophilia and AIDS/HIV Network for the Dissemination of Information (“HANDI”) at the same address (telephone 800-42-HANDI).
hemophilia A classical hemophilia, a sex-linked condition due to deficiency of coagulation factor VIII; see hemophilia.
hemophilia B a form similar to hemophilia A but due to a deficiency of coagulation factor IX; called also Christmas disease. See hemophilia.
hemophilia C an inherited disorder caused by a lack of coagulation factor XI.. It has been observed mostly in persons of Ashkenazi Jewish ancestry and is characterized by recurring episodes of minor bleeding and mild bruising, severe prolonged bleeding after surgical procedures, and prolonged recalcification and partial thromboplastin times. Called also plasma thromboplastin antecedent deficiency, PTA deficiency, and Rosenthal syndrome.

he·mo·phil·i·a A

[MIM*306700-various]
hemophilia due to deficiency of factor VIII; an X-linked recessive condition, occurring almost exclusively in male humans and also affecting several breeds of dogs, characterized by prolonged clotting time, decreased formation of thromboplastin, and diminished conversion of prothrombin.
Synonym(s): classic hemophilia

hemophilia A

a hereditary blood disorder usually expressed in males that is transmitted as an X-linked recessive mutation causing a deficiency of coagulation factor VIII. Hemophilia A is sometimes named classic hemophilia. See also coagulation factor, hemophilia.

hemophilia A

Classical hemophilia, factor VIII deficiency hemophilia Hematology An X-R coagulopathy due to a marked ↓ of factor VIII Physiology Factor VIII circulates as a noncovalent complex with von Willebrand factor, which once cleaved by thrombin or by factor Xa enables factor VIII to bind to phospholipid surfaces of damaged cells and adherent activated platelets Clinical Hemophilia A is heterogenous as moderate–1—4% normal; or mild–5—25% normal factor VIII deficiency occurs; classic findings–joint hemorrhage of knee > elbow >etc, muscle hemorrhage, bruising, prolonged and potentially fatal post-traumatic or post-op hemorrhage Lab Normal platelets, normal prothrombin time, ↑ aPTT, ↓ factor VIII Treatment Recombinant factor VIII. See AIDSgate, Factor VIII.

he·mo·phil·i·a A

(hē'mō-fil'ē-ă)
The inherited blood disorder resulting from a deficiency of factor VIII, occurring almost exclusively in males, and characterized by prolonged clotting time, decreased formation of thromboplastin, and diminished conversion of prothrombin.
Synonym(s): classic hemophilia, haemophilia A.

Hapsburg,

Austrian royal family who ruled most of central and part of western Europe for centuries.
disease of the Hapsburgs - factor VIII deficiency causing blood coagulation disorder. Synonym(s): classic hemophilia; hemophilia A

he·mo·phil·i·a A

(hē'mō-fil'ē-ă) [MIM*306700-various]
Blood disorder due to deficiency of factor VIII; occurring almost exclusively in male humans characterized by prolonged clotting time, decreased formation of thromboplastin, and diminished conversion of prothrombin.
Synonym(s): classic hemophilia, haemophilia A.

hemophilia

a condition characterized by impaired coagulability of the blood, and a strong tendency to bleed. See also deficiency of the following clotting factors, afibrinogenemia and hypoprothrombinemia, and proconvertin, stuart factor, plasma thromboplastin antecedent, hageman factor and fibrin stabilizing factor.

hemophilia A
classical hemophilia, due to deficiency of clotting factor VIII-C; occurs in dogs, horses and cats and is transmitted by the female to the male as a sex-linked recessive abnormality.
hemophilia B
a form similar to classical hemophilia but due to a deficiency of clotting factor IX; called also christmas disease and factor IX deficiency. Occurs in dogs and cats.
hemophilia C
in dogs an autosomal dominant form due to deficiency of clotting factor XI (plasma thromboplastin antecedent). Called also factor XI deficiency. The disease also occurs in cattle but the clinical disease is minor and it is inherited as a recessive character.
double hemophilia
dogs with both hemophilia A and hemophilia B have been produced experimentally.
vascular hemophilia
deficiency of clotting factor VIII and factor VIII-related antigen occurs in many breeds of dogs, particularly Doberman Pinschers, and in rabbits and pigs. See also von willebrand's disease.
References in periodicals archive ?
in previously treated patients with haemophilia A from 19 countries who had been enrolled in the pivotal guardian(TM)1 and guardian(TM)3 trials.
is a B-domain truncated recombinant human coagulation factor VIII for the treatment and prevention of bleeding in patients with haemophilia A.
People with haemophilia A are either missing or have a malfunctioning factor VIII protein, which is essential for proper blood clotting.
Sobi and Biogen are partners in the development and commercialisation of Elocta/Eloctate/rFVIIIFc for haemophilia A.
Guardian(TM)2 is the extension of the pivotal guardian(TM) clinical programme, one of the largest and most comprehensive pre-registration clinical trial programmes in haemophilia, with more than 210 severe haemophilia A patients treated.
has been approved by the FDA (October 2013) and EMA (November 2013) for the treatment and prophylaxis of bleeding in patients with haemophilia A.
Molecules in the clinical development pipeline include N8-GP, designed to provide a longer half-life and the potential to reduce the treatment burden for people with haemophilia A and N9-GP, a long-acting recombinant factor IX for haemophilia B that has the potential to significantly reduce bleeding with weekly injections.
The incidence of inhibitors complicating treatment of haemophilia A and B is approximately 30% in haemophilia A and 3 to 5% in haemophilia B patients.