A Novel Fibrinogen Mutation p.BßAla68Asp Causes an Inherited Dysfibrinogenemia.

OBJECTIVE:  Our study aimed to analyze the phenotype and genotype of a pedigree with inherited dysfibrinogenemia, and preliminarily elucidate the probable pathogenesis.

METHODS:  The one-stage clotting method was used to test the fibrinogen activity (FIB:C), whereas immunoturbidimetry was performed to quantify the fibrinogen antigen (FIB:Ag). Furthermore, DNA sequence analysis was conducted to confirm the site of mutation. Conservation analysis and protein model analysis were performed using online bioinformatics software.

RESULTS:  The FIB:C and FIB:Ag of the proband were 1.28 and 2.20 g/L, respectively. Gene analysis revealed a heterozygous c.293C > A (p.BßAla68Asp) mutation in FGB . Bioinformatics and modeling analysis suggested that the missense mutation could potentially have a deleterious effect on fibrinogen.

CONCLUSION:  The BßAla68Asp mutation in exon 2 of FGB may account for the reduced FIB:C levels observed in the pedigree. To our knowledge, this point mutation is the first report in the world.