Health encyclopaedia

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Causes of Haemophilia

Haemophilia A is due to the absence of Factor VIII. Haemophilia B is due to absence of Factor IX. These clotting factors are two of the many elements necessary for normal blood coagulation.

The disease is passed from mother to son on the X chromosome. (The father passes a Y chromosome to their son). Thus women can be carriers having one affected chromosome and transmitting the disease to 50 per cent of their male offspring.

In about 30 per cent of cases, however, there is no family history of haemophilia, these cases arise as a result of new mutations occurring in the cells that produce eggs or sperms in the parents.

The severity of haemophilia varies with the level of Factor VIII activity in the individual and in severe cases this may be less than two per cent of normal.

• HaemophiliaHaemorrhoidsHair lossHand, foot and mouth diseaseHangoverHay feverHead injuryHead liceHeadacheHealth and safety at workHealth recordsHearing and vision tests for childrenHearing impairmentHearing testsHeart attackHeart blockHeart failureHeart lung transplantHeartburnHeatstrokeHepatitisHepatitis AHepatitis BHepatitis CHernia, hiatusHernia, inguinalHiccupHip replacementHIV and AIDSHome testsHomeopathyHormone replacement therapyHospitals, admissionHospitals, childrenHospitals, dischargeHughes syndromeHuntington's diseaseHydrocephalusHydronephrosisHyperglycaemiaHyperlipidaemia and lipid-lowering medicinesHypoglycaemiaHypothermiaHysterectomy

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