Severe Hemophilia A and Congenital Antithrombin Deficiency: A Case of Natural Hemostatic Rebalancing

Rare cases of co-inherited bleeding and thrombotic disorders offer a unique window into the complexity of hemostatic regulation. We report one such case-severe hemophilia A coexisting with congenital antithrombin (AT) deficiency-which challenges traditional diagnostic expectations and offers insight into both natural compensatory mechanisms and the rationale behind emerging rebalancing therapies such as Fitusiran. We believe this case underscores the importance of integrating coagulation, global hemostasis and genetic assessments in hemophilia care, and invites the field to consider how opposing hemostatic defects may reshape both clinical expression and treatment paradigms.