KM GENOTYPING USING POLYMERASE CHAIN REACTION-ALLELE SPECIFIC OLIGONUCLEOTIDE IN KOREANS

The allotype of human immunoglobulin kappa light chain constant region gene (IGKC) has been identified by the serological assay or DNA typin g method. The three allotypes km1, Km*1,2 and Km*3 have amino acid su bstitutions at positions of codons 153 and 191 in the kappa Light chai n constant region. The Km allotypes were designated as follows: Kmn1 has valine (GTC) at position 153 and leucine (CTC) at 191; Km1,2 has Ala(153) (GCC) and Leu(191) (CTC); Km3 has Ala(153) (GCC) and Val(191 ) (GTC). In this study, polymerase chain reaction-allele specific olig onucleotide (PCR-ASO) was used to provide a specific allelic typing sy stem for the IGKC gene in 213 unrelated Koreans. For Km genotyping, th e IGKC coding regions plus 35 bp of the 3' untranslated regions were a mplified with specific primers. Amplified genes were hybridized with K m ASO probes at positions of codons 153 and 191 and were detected usin g a colorimetric detection method. The frequencies of Km1,2/Km*1,2, K m1,2/Km*3, and Km*3/Km*3 were 17.8% (n=38), 51.7% (n=110), and 30. 5% (n=65), respectively. The estimated allele frequencies for Km1,2 and Km3 were 0.43 and 0.56, respectively. The homozygote or the heterozy gote of Km1 was not observed in this study. The PCR-ASO method distin guished the alleles Km3, Km*1,2, and Km*1 and also distinguished the homozygote from heterozygote. Km frequencies vary significantly among various populations. Km3 in Koreans was very similar to those observe d in northern Chinese, Japanese, and the native people of British Colu mbia. It was lower than that reported in Caucasian, Indian, or souther n Chinese.