LAUSR

Antithrombin (AT), encoded by the gene SERPINC1, is a serine protease inhibitor whose deficiency causes a severe form of dominantly inherited thrombophilia. de la Morena-Barrio et al describe 2 novel variants of AT with altered glycosylation profiles that were identified in 4 unrelated families with thrombophilia. This study finds that although these mutations are clearly associated with abnormal thrombosis, carriers are not identified using routine testing for AT deficiency. These discoveries provide insight into the regulation of AT function, and they have implications for the investigation of severe thrombophilia, particularly in families.