Congenital Dysfibrinogenemia with Recurrent Venous Thrombosis and Concomitant von Willebrand Syndrome: A Case Report

Introduction Congenital dysfibrinogenemia is a rare coagulation disorder associated with both bleeding and thrombotic manifestations. Management becomes particularly challenging when additional hemostatic abnormalities are present. Fig. 1 Fibrinogen Aktivität und Antigen im Verlauf Method We present the case of a 41-year-old female with a heterozygous pathogenic variant in the FGG gene (p.Ala108Gly). Clinical course, laboratory findings, and therapeutic management were documented over several years, including two thrombotic events [ 1 ] [ 2 ] [ 3 ] [ 4 ] [ 5 ]. Results The patient presented with significant mucocutaneous bleeding (ISTH-BAT score: 12), menorrhagia, and postoperative hemorrhage. Despite this bleeding phenotype, she also developed recurrent left subclavian vein thrombosis in 2021 and 2024 in the context of thoracic outlet syndrome. Laboratory monitoring revealed consistently reduced fibrinogen activity compared to antigen levels, indicating dysfibrinogenemia, and reduced von Willebrand factor (VWF) activity with low-to-borderline antigen levels, consistent with a concomitant mild type-1 von Willebrand syndrome. After the recurrent thrombosis, therapeutic anticoagulation with tinzaparin was initiated and dose-adjusted to achieve anti-Xa activity of 0.6–0.8 IU/mL. Under anticoagulation, menstrual bleeding with clots was aggravated. This case illustrates the clinical complexity of balancing hemorrhagic and thrombotic risks in congenital dysfibrinogenemia with additional hemostatic defects. Fig. 2 Von-Willebrand-Parameter im Verlauf Conclusion The coexistence of dysfibrinogenemia, von Willebrand syndrome, and venous thrombosis highlights the need for individualized management. Careful balancing of anticoagulation and bleeding prophylaxis is essential, particularly in women of reproductive age. Publication History Article published online: 17 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany