Identification of compound heterozygous variants of F12 gene in a pedigree affected with inherited coagulation factor XII deficiency / 中华医学遗传学杂志

ABSTRACT

OBJECTIVE@#To explore the molecular pathogenesis for a pedigree affected with hereditary coagulation factor XII (FXII) deficiency.@*METHODS@#Potential variant of the F12 gene was analyzed by PCR and Sanger sequencing. Expression plasmids were constructed by site-directed mutagenesis based on the wild-type and transiently transfected into 293T cells. FXIIC and FXIIAg of the expression products were determined in the supernatant and cell lysate. Western blotting was used to verify the identify of the protein.@*RESULTS@#Gene sequencing revealed that the proband has carried 46TT genetype and heterozygous p.Glu502Lys variants in exon 13, and a heterozygous p.Gly542Ser variant in exon 14 of the F12 gene. Transfection experiment suggested that the FXIIC and FXIIAg of p.Glu502Lys variant in the supernatant were 28% and 24%, compared with the wild-type (100%) and FXIIAg of cell lysates was 39% compared to the wild-type (100%). The FXIIC and FXIIAg of p. Gly542Ser variant in the supernatant were 32% and 17% and the FXIIAg of cell lysates was 59%.@*CONCLUSION@#The 46TT genetype, p.Glu502Lys and p.Gly542Ser variants of the F12 gene probably underlie the low FXII level in the proband. As shown by in vitro experiment, the p.Glu502Lys and p.Gly542Ser variants can both inhibit the synthesis and secrection of the FXII protein.