The synonymous nucleotide substitution RHD RHD RHD 1056C>G alters mRNA mRNA splicing associated with serologically weak D phenotype

摘要

Background D antigen is one of the most clinically significant blood group antigens. Variation of the RHD gene can cause weak D or partial D phenotypes. While most variations are missense substitutions with amino acid changes, those without are called “silent” or “synonymous” substitutions. Synonymous substitutions often have little effect on the protein, not altering the phenotype. However, effect on splicing can affect end‐product protein. We report a new synonymous variation, RHD 1056CG, that resulted in weak D phenotype, and predicted its effect with various in silico methods. Methods Serologic testing of the D antigen with full sequencing of the RHD gene was done. Human Splice Finder was used to predict the effect of this variation, and validation of this method was done with all known RHD variations reported in the literature. Results RHD 1056CG was predicted to cause the formation of an exonic splicing silencer ( ESS ) site. The creation of new ESS site potentially inhibits the splicing event, resulting alteration of splicing. This is similar to remodeling of splice acceptor or donor site, as this kind of deep exonic variation could affect the D antigen's quality or quantity. This is in concordance with serologic results, which showed only delayed weak agglutination to anti‐D reagents. Conclusions The analytic methods we applied showed good correlation with the actual phenotype, along with concordant results when analyzing other known variants reported in the literature. We conclude that RHD 1056CG results in serologic weak D phenotype.