An absence or reduced level of Antithrombin III leading to an increased risk for thrombosis.

Synonyms: Antithrombin 3 Deficiencies, Deficiencies, Antithrombin 3, Antithrombin III Deficiencies, Antithrombin III Deficiency, Deficiency, Antithrombin III, Deficiency, Antithrombin 3, Antithrombin 3 Deficiency, Congenital Antithrombin III Deficiency, Hereditary Antithrombin Deficiency, Deficiencies, Antithrombin III