title: Hereditary antithrombin III deficiency: biochemical aspects.
abstract: Since the description of the first thrombophilic family with congenital AT-III deficiency, increasing numbers of different types of the condition have become evident. Initially the anomaly seemed to be homogeneous and simple: the three main characteristics of AT-III (thrombin inactivating and heparin cofactor activity, antigen concentration) were decreased. This type of AT-III deficiency (type 1) was later divided into type 1a and 1b on the basis of the heparin affinity of the AT-III molecule. The first family with a different qualitative AT-III disorder (type 2) was described by our group in 1974. In the members of this family the AT-III antigen concentration was normal, but the molecule had no functional activity (AT-III Budapest). In the last few years some new variants of type 2 hereditary AT-III disorders have been observed; they are characterized by a loss of one or more functional properties of the AT-III molecule.
mesh_terms: D000941:Antigens; D000990:Antithrombin III / Q000145:classification / Q000276:immunology; D020152:Antithrombin III Deficiency; D002846:Chromatography, Affinity; D000013:Congenital Abnormalities; D003378:Counterimmunoelectrophoresis; D014644:Genetic Variation; D005826:Genetics, Medical; D006493:Heparin / Q000276:immunology; D006801:Humans
chemical_list: D000941:Antigens; D000990:Antithrombin III; D006493:Heparin