Congenital Afibrinogenemia With Coexisting Factor V Leiden Mutation Complicated by Budd-Chiari Syndrome: A Case Report.

Congenital afibrinogenemia is a rare autosomal recessive bleeding disorder characterized by the complete absence of fibrinogen, a key protein in the coagulation cascade. Patients usually present with hemorrhagic manifestations, ranging from mild mucocutaneous bleeding to life-threatening events, such as intracranial or gastrointestinal hemorrhage. Paradoxically, thrombotic complications have been increasingly described, underscoring the dual nature of the disease. We report a case of a 15-year-old female with congenital afibrinogenemia who presented with abdominal pain and was diagnosed with Budd-Chiari syndrome (BCS), a rare but potentially fatal hepatic venous outflow obstruction. Genetic testing further revealed the presence of a heterozygous factor V Leiden mutation, a well-known inherited thrombophilia that likely contributed to the development of BCS in this patient. She was treated with fibrinogen replacement and anticoagulation therapy, with careful monitoring to balance bleeding and thrombotic risks. The patient showed clinical improvement and remained stable at three-month follow-up. The coexistence of a bleeding disorder and a prothrombotic mutation illustrates the complexity of clinical management, as therapeutic strategies must balance hemostatic replacement with anticoagulation while minimizing risks on both sides. This case highlights the need for heightened awareness of thrombotic complications in congenital afibrinogenemia, the importance of investigating concomitant thrombophilic risk factors, and the necessity of an individualized, multidisciplinary approach to optimize outcomes in rare coagulation disorders.