Abstract:

Objective To assess the mutation in exon 8 of C1 esterase inhibitor （C1INH） gene in a patient with hereditary angioedema （HAE）. Methods Genomic DNA was extracted from a female patient with HAE as well as her mother and a normal human control. The fragment of exon 8 of C1INH gene was amplified by PCR and inserted into plasmid carrier pUC19 with the help of ligase. Then, the recombinant plasmid was transformed into competent cells of E. coli TG1 strains. After culture of positive transformant, plasmid DNA was extracted and subjected to sequencing. SDS-PAGE and Western blot were performed on the sera of the patient to detect the concentration and function of C1INH protein. Results An A1677G mutation at exon 8 of C1INH gene, which resulted in a substitution of isoleucine to valine at codon 440, was found in the patient who suffered from HAE type I. Additionally, SDS-PAGE and Western blot revealed that the molecular weight of C1INH protein was 96 000, but not 105 000 observed in normal human control. Conclusion The newly identified mutation I440V, which is located at P4 residue of reactive center loop in C1INH, may result in conformational alteration of C1INH.