A novel nonsense mutation in the antithrombin III gene (Cys-4-->stop) causing recurrent venous thrombosis

We describe a novel mutation identified in the antithrombin III (AT-III) propeptide responsible for AT-III deficiency. This mutation, a C to A transversion in exon 2, converts the cysteine at position -4 into a stop codon (TGC-->TGA). In this family with severe thrombophilia, the mutation co-segregates with the clinical phenotype.