Presence of nucleotide substitutions in the ABO promoter in individuals with phenotypes A sub(3) and B sub(3)

• Published in: Vox sanguinis 2016-04, Vol.110 (3), p.285-287
• Main Authors: Isa, K, Yamamuro, Y, Ogasawara, K, Yabe, R, Ogiyama, Y, Ito, S, Takahashi, Y, Kominato, Y, Sano, R, Uchikawa, M
• Format: Article
• Language: English
• ISSN: 0042-9007; 1423-0410
• DOI: 10.1111/vox.12363

Recently, the involvement of mutation and deletion of transcription regulatory elements in the B sub(m), A sub(m), A sub(3) and B sub(3) phenotypes has been reported. In the present study, we carried out genetic analysis of individuals with A sub(3) and B sub(3) using peptide nucleic acid-clamping PCR to exclude amplification of O alleles. Two single-point mutations, -76G>C and -68G>T, were found in the ABO promoter on the A-allele in three A sub(3) individuals and on the B allele in a B sub(3) individual, respectively. Transient transfection of luciferase reporter plasmids carrying the same mutations into K562 cells revealed decreased luciferase activity in comparison with that carrying the wild-type promoter. These observations suggest that the mutations downregulate the promoter activity, leading to reduction in A- or B-antigen expression on red blood cells in individuals with the A sub(3) and B sub(3) phenotypes.