RESUMO
BACKGROUND: Molecular and genetic studies of the complement component C9 have never been reported in Korea. METHODS: We have checked the TaqI polymorphism of the C9 gene in 52 randomly selected adult Koreans. Southern blot analysis was carried out to detect the restriction fragment length polymorphism (RFLP) of the C9 gene. The fragments of human C9 cDNA were hybridized with the TaqI digested genomic DNA. RESULTS: The functional levels of complements in all subjects were measured at 84.4+/-3.8% by hemolytic assay, which indicates that the subjects have functionally normal complement systems. Fifty-four percent of the individuals were found to have the C9 genes that contain the constant fragments only. It seems that the undetected TaqI site may be located in the intron of the C9 gene. The silent mutation of C->T transversion was found in exon 1 of the C9 gene through polymerase chain reaction-single strand conformational polymorphism, but no mutation was found in exon 4 of the C9 gene. CONCLUSIONS: We could not find TaqI polymorphism in exons of the C9 gene in 52 Koreans.