Severe factor X deficiency due to a homozygous mutation (Cys364Arg) that disrupts a disulphide bond in the catalytic domain

Severe factor X deficiency (<0.01 IU mL(-1)) is a rare disorder producing a major bleeding tendency including umbilical cord, joint and intracranial haemorrhage. We present the first case of a child homozygous for a g.1177T > C missense alteration, predicted to disrupt the catalytic domain, and resulting in severe FX deficiency. The child suffered intracranial haemorrhage and now receives regular prophylaxis with a prothrombin complex concentrate. Our experience and a review of the literature suggest that optimal frequency of dosing is likely to be two or three times weekly and that the risk of thrombosis is very small.

An unusual cause of bruising in an 80-year-old woman

PRESENTATION

a previously fit 80-year-old woman presented with a 2-week history of spontaneous and extensive bruising affecting all four limbs. The severity was such that she required a transfusion of 8 units of blood.

RESULTS OF INVESTIGATIONS

a markedly prolonged activated partial thromboplastin time which was only partially corrected with normal plasma; tests for lupus anticoagulant were negative. Factor VIII levels were reduced and the Bethesda assay indicated an acquired inhibitor to factor VIII. She was treated with a combination of intravenous immunoglobulin and immunosuppression.

OUTCOME

the response to treatment was excellent, with a marked reduction in anti-factor VIII antibody levels and resolution of the bruising over the next few weeks.