OBJECTIVETo explore the molecular pathogenesis and clinical phenotypes in 10 probands with inherited fibrinogen (Fg) deficiency.

METHODSThe diagnosis of hereditary Fg deficiency was validated by prothrombin time (PT), thrombin time (TT), Fg activity (Fg:C) and Fg antigen (Fg:Ag) in plasma. All of the exons and their flanking sequences of the Fg gene were analyzed by direct sequencing. Detected mutations were confirmed by reverse sequencing.

RESULTSThe ranges of Fg:C and Fg:Ag in the 10 probands were 0.52-0.91 g/L and 0.62-2.98 g/L, respectively. Five of the probands had type I disorders, and 5 had type II disorders. Seven point mutations were identified, among which 6 have located in the D region. γThr277Arg, γAsp316His, γTrp208Leu and Lys232Thr were novel mutations, and αArg19Ser was first reported in Chinese. Four probands had the same mutation site (γArg275). As to the clinical manifestation, probands with type I disorders were asymptomatic or with mild or medium symptoms, while those belonged to type II disorders had moderate or serious symptoms. Two probands have carried an Arg275Cys mutation but had different clinical manifestations.

CONCLUSIONMutations of the Fg gene seem to aggregate to the D region of FGG in our region, and Arg275 is a common mutation. However, no correlation has been found between the mutation site and clinical manifestations.