Obstetrics & gynaecology

Heavy periods? You might have an undiagnosed bleeding disorder

About 30 per cent of all women report heavy menstrual periods at some point during their reproductive years. Up to 15 per cent of these have an underlying bleeding disorder and yet most have never been diagnosed, leaving ...

Medical research

Unraveling mysteries in the blood

Queen's University researcher Paula James has revealed women who are carriers of hemophilia A, an inherited bleeding disorder, experience abnormal bleeding in about 30 per cent of cases. Dr. James is working to unravel the ...

Medications

FDA OKs new therapy for some hemophilia patients

U.S. regulators have approved the first new treatment in nearly two decades to prevent internal bleeding in certain patients with hemophilia, an inherited blood-clotting disorder.

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Haemophilia

Haemophilia (English pronunciation: /hiːməˈfɪliə/; also spelled hemophilia in North America, from the Greek haima αἷμα 'blood' and philia φιλος 'love') is a group of hereditary genetic disorders that impair the body's ability to control blood clotting or coagulation, which is used to stop bleeding when a blood vessel is broken. Haemophilia A (clotting factor VIII deficiency) is the most common form of the disorder, present in about 1 in 5,000–10,000 male births. Haemophilia B (factor IX deficiency) occurs in around 1 in about 20,000–34,000 female births.

Like most recessive sex-linked, X chromosome disorders, haemophilia is more likely to occur in males than females. This is because females have two X chromosomes while males have only one, so the defective gene is guaranteed to manifest in any male who carries it. Because females have two X chromosomes and haemophilia is rare, the chance of a female having two defective copies of the gene is very low, so females are almost exclusively asymptomatic carriers of the disorder. Female carriers can inherit the defective gene from either their mother or father, or it may be a new mutation. Although it is not impossible for a female to have haemophilia, it is unusual: a female with Haemophilia A or B would have to be the daughter of both a male haemophiliac and a female carrier, while the non-sex-linked Haemophilia C, which can affect either sex, is extremely rare.

Haemophilia lowers blood plasma clotting factor levels of the coagulation factors needed for a normal clotting process. Thus when a blood vessel is injured, a temporary scab does form, but the missing coagulation factors prevent fibrin formation, which is necessary to maintain the blood clot. A haemophiliac does not bleed more intensely than a person without it, but can bleed for a much longer time. In severe haemophiliacs even a minor injury can result in blood loss lasting days or weeks, or even never healing completely. In areas such as the brain or inside joints, this can be fatal or permanently debilitating.

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