[FXI gene mutations in two pedigrees of congenital clotting factor XI deficiency].

To identify the FXI gene mutations in two Chinese pedigrees of congenital factor XI deficiency.The peripheral blood samples were collected from the probands and their family members and the plasma FXI:C and FXI:Ag were determined. All the exons and exon-intron boundries of FXI gene were amplified with PCR and sequenced thereafter.A nonsense mutation Trp228stop and two missense mutations Glu323Lys and Leu172Pro were disclosed in the two pedigrees. All mutations existed in a heterozygous state.The FXI gene mutations Trp228stop, Glu323Lys and Leu172Pro attribute to the pathogenesis of the congenital factor XI deficiency in Chinese. The Leu172Pro is identified for the first time.