Novel mutations p.Lys327X and p.Leu424CysfsX8 underlying congenital factor Ⅺ deficiency

Objective: To analyze the phenotype and genetic mutations in a pedigree affected with factor Ⅺ (FⅪ) deficiency.

Methods: Activated partial thromboplastin time (APTT), FⅪ activity (FⅪ:C) and FⅪ antigen (FⅪ:Ag) were determined for the proband and his family members. All exons and exon-intron boundaries of the FⅪ gene of the proband were analyzed by direct sequencing. Suspected mutation was verified in his family members.

Results: The proband had APTT of 82.4 s, FⅪ:C of 0.8%, and FⅪ:Ag of <1%. DNA sequencing showed that he has carried c.1033A>T (Lys327X) mutation in exon 10 and c.1325delT (Leu424CysfsX8) mutation in exon 12 of the FⅪ gene. His elder sister, son, daughter, two granddaughters and one grandson were heterozygous carriers of the c.1033A>T mutation, while his older sister and younger brother were heteozygous carriers of the c.1325delT mutation. Analysis using Mutation Taster software showed that both p.Lys327X and p.Leu424CysfsX8 may affect the function of protein and lead to the corresponding disease.

Conclusions: The novel mutations of Lys327X and Leu424CysfsX8 of the the FⅪ gene probably underlie the pathogenesis of congenital coagulation factor Ⅺ deficiency in this pedigree.