Identification of eight exonic variants in the SLC4A1, ATP6V1B1 and ATP6V0A4 gene that alter RNA splicing by minigene assay

Primary distal renal tubular acidosis (dRTA) is a rare tubular disease associated with variants in SLC4A1, ATP6V0A4, ATP6V1B1, FOXⅠ1 or WDR72 genes. Currently, there is growing evidence that all types of exonic variants can alter splicing regulatory elements, affecting the pre-mRNA splicing process. This study was to determine the consequences of variants associated with dRTA on pre-mRNA splicing combined with predictive bioinformatics tools and minigene assay. As a result, among the 15 candidate variants, 8 variants distributed in SLC4A1 (c.1765C>T, p.Arg589Cys), ATP6V1B1( c.368G>T, p.Gly123Val; c.370C>T, p.Arg124Trp; c.484G>T, p.Glu162* and c.1102G>A, p.Glu368Lys) and ATP6V0A4 genes (c.322C>T, p.Gln108*; c.1571C>T, p.Pro524Leu and c.1572G>A, p.Pro524Pro) were identified to result in whole or part of exon skipping by either disruption of ESEs and generation of ESSs, or interference with the recognition of the classic splicing site, or both. To our knowledge, this is the first study on pre-mRNA splicing of exonic variants in the dRTA-related genes. These results highlight the importance of assessing the effects of exonic variants at the mRNA level and suggest that minigene analysis is an effective tool for evaluating the effects of splicing on variants in vitro