Thrombophilia in ethnic Arabs in Kuwait.

One hundred and thirty unrelated patients with recurrent deep venous thrombosis were studied over a period of 4 years (1986-1990) in order to determine the possible etiology. Protein C levels were estimated in plasma both by chromogenic substrate assay and by immunoassay. Protein S levels in plasma was determined by immunoassay using antisera to human protein S. Antithrombin III (AT-III) was assayed using monospecific rabbit antiserum to human AT-III. Fifteen patients were found to have hereditary protein C deficiency (11.52%). Family studies revealed autosomal recessive inheritance in one patient and a dominant pattern in the remaining 14 patients. Protein S deficiency was found in eight cases (6.1%), AT-III deficiency was established in five cases (3.8%) and a fibrinolytic defect in 33 cases (25.4%). Thrombosis of visceral and cerebral vessels and a positive family history were more frequently found among patients who had hereditary deficiency of one or the other antithrombotic factor. Thrombophlebitis of superficial veins was found to be very common in patients with protein C and protein S deficiency and virtually absent in AT-III deficiency. The high frequency of protein C and protein S deficiency in this ethnic group is attributed to the high frequency of consanguinity.