Congenital Hypodysfibrinogenemia due to γ326Cys→Tyr Mutation: Third Ever-Described Case Associated with Recurrent Venous Thrombosis and COVID Vaccine

Introduction: Congenital fibrinogen disorders are a heterogenous group of fibrinogen defects.

Case presentation: Here, we describe hypodysfibrinogenemia in a 33-year-old female patient with provoked recurrent deep vein thrombosis (DVT) diagnosed based on decreased functional and antigenic fibrinogen levels with a decreased functional/antigenic fibrinogen ratio. Definitive diagnosis of congenital hypodysfibrinogenemia is done by genotyping using whole-exome sequencing, which identified the γ326Cys→Tyr mutation combined with single-nucleotide polymorphisms: rs2070011 and rs2070018 in FGA and rs1049636 in FGG. Fibrin structure assays showed reduced maximum polymerization rate. The mother of the proband shares the same γ326Cys→Tyr mutation and experienced a provoked DVT.

Conclusion: Our case with DVT is the third ever-described occurrence of the mutation γ326Cys→Tyr that is associated with hypodysfibrinogenemia. The mechanism by which this mutation induces thrombosis remains unknown. Due to the high recurrence risk of thrombosis, the patient was treated with long-term reduced dose of rivaroxaban (10 mg daily) as secondary prophylaxis.

Keywords: Congenital fibrinogen disorder; Hypodysfibrinogenemia; Thrombosis; γ chain.