Antithrombin III‐Amiens: A new family with an Arg47 → cys inherited variant of antithrombin iii with impaired heparin cofactor activity

A family with an antithrombin III variant (AT-III-Amiens) demonstrating abnormal heparin cofactor activity is described. Amplification and direct sequencing of genomic DNA by the polymerase chain reaction procedure permitted the identification of an Arg47----Cys mutation in exon 2 of the variant antithrombin III gene.