RESUMEN
BACKGROUND: Complete sequencing, except for intron 1, of the ABO allele in some populations has been reported. However, so far, one report on complete sequencing of the ABO gene in three Korean families with normal ABO phenotypes has been published. This study aimed to establish a reference database of common ABO alleles in Koreans. METHODS: Screening of common ABO alleles, including homozygote form, was performed by direct sequencing of exons 6 and 7 and by real-time PCR using displacing probes in 95 healthy donors. Genomic DNA from the common ABO group (n=8) and some ABO subgroups (n=7) was used in complete sequencing (except for intron 1) of the ABO allele. RESULTS: The sequences of B101/B101 (n=1), O01/O01 (n=1) were identical with the corresponding sequences registered in Genebank. A102 and A105 had a common point mutation, 1142 C>T in intron 4. A102 (n=3/11) and O02 (n=3/3), selected by sequencing of exons 6 and 7, were reclassified into A105 and O65 by whole genomic sequencing, respectively. Analytic results for ABO subgroups were as follows: B3, B101/O01 (n=3) and B101/O02 (n=1); A1B3, A102/B101 (n=1) and A105/B101 (n=1); Ax, A102/O01 (n=1). CONCLUSION: We established a reference database of common ABO alleles in Koreans and found that the molecular basis of introns of ABO alleles in the Korean population differs from that reported in previous studies of other populations.