A point mutation of protein C gene in a congenital protein C deficiency pedigree

Objective To study the phenotypes and genotypes of a protein C (PC) deficiency pedigree.Methods Immunoassay (ELISA) was used for PC antigen and activated PC(APC) detection,PCR for amplification of the fragment of protein C gene exon Ⅱ to exon Ⅸ, single strand conformation polymorphism(SSCP) for difference of denatured cDNA and DNA sequencing for gene mutation. Results Four members in the pedigree were found to be PC antigen levels between 34.3%～67.8% and PC activity between 22%～49% which are lower in comparison with normal references (80%～120% and 70%～130%, respectively). A G to A mutation in exon Ⅶ of the protein C gene at 6 219 position was identified in 9 members. This mutation resulted in the substitution of Arg for Gln at 169 amino acid.Conclusion The proband is of heterozygosity. The G6219 A mutation in exon Ⅶ of the protein C gene leads to the substitution of Arg 169 Gln. This mutation is reported for the first time in China.