Objective: To explore the clinical phenotype of a family affected with congenital dysfibrinogenemia and potential mutations underlying the disease.
Methods: Coagulation testing and hepatorenal function testing were conducted on 18 individuals from three generations. Plasma fibrinogen was extracted and analyzed with SDS-PAGE electrophoresis. All of the exons and flanking sequences of fibrinogen FGA, FGB, FGG genes were analyzed by PCR, and the products were subjected to Sanger sequencing.
Results: Hepatorenal function, prothrombin time and activated partial thromboplastin time of the proband were all normal. However, his thrombin time was significantly prolonged. Fibrinogen activity was decreased, while the concentration of antigen was in the normal range. The results of his mother, brother, and nephew were similar. DNA sequencing has confirmed that the proband, his mother, brother, and nephew have all carried a g.5877G>A mutation in the exon 8 of the FGG gene, which resulted in replacement of arginine (Arg) by histidine (His) at position 275.
Conclusion: The Arg275His mutation of the fibrinogen gamma chain probably underlies the pathogenesis of congenital dysfibrinogenemia in this family.