A novel γ-chain mutation p.Asp318His in a Chinese family with dysfibrinogenemia.

Background: Congenital dysfibrinogenemia is characterized by reduced fibrinogen activity, but normal immunoreactive fibrinogen levels. Here, we present a novel case with an elevated risk of thrombosis.

Methods: Coagulation assays, gene analysis, in silico tools, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), fibrin polymerization, thrombin generation assay, and electron microscopy scanning were utilized to elucidate the pathogenic mechanism.

Results: The proband manifested with a normal immunologic fibrinogen (2.13 g/l) but reduced functional fibrinogen (0.39 g/l). Subsequent genetic analysis unveiled a novel heterozygous mutation, c.1030G>C (p.Asp318His), in the γ-chain D domain of fibrinogen, which was highly conserved in homologous species and led to enhanced thrombin generation capability. The ability of the proband's fibrinogen to polymerize was significantly impaired, with decreased final turbidity. Scanning electron microscopy indicated that the fibers of the proband were thinner than normal, with smaller pores. Thromboelastography (TEG) results demonstrated prolonged K time, decreased angle value, and a normal confidence interval value in the proband.

Conclusion: We present a novel case displaying the γAsp318His mutation, which resulted in dysfibrinogenemia.