c.98 + 3A>G and c.155 + 1G>T splice-site variants in the ABO*B.01 allele lead to weak antigen expression in the Chinese individuals

Background: gene across multiple subtypes have been identified. These variants are located in the coding region, the erythroid-specific regulatory element region of intron 1, splice sites, and other non-coding regions. However, data regarding the functional analysis of these variants remain limited. In this study, we analyzed the function of two splice-site variants in ABO subtypes. Methods: using a minigene splicing assay. Furthermore, stable cell lines expressing ABO cDNA with exon 2 or 3 deletions were established to evaluate their effects on antigen expression utilizing serology, flow cytometry, and glycosyltransferase activity assays. Results: cDNA containing deletions in exons 2 or 3, as analyzed by cytometry and serological methods. In addition, no enzymatic activity was detected in the supernatant of these transfected cells. Conclusions: gene may induce aberrant mRNA splicing, leading to skipping of exons 2 or 3, and resulting in the formation of a nonfunctional glycosyltransferase.