Polymorphisms of RhD<SUP>Va</SUP> and a New RhD<SUP>Va</SUP>-Like Variant Found in Japanese Individuals

Background and Objectives: Red cell type RhD^Va lacks epD1 and 5 and is encoded by hybrid RHD-CE(5)-D alleles. We analyzed RhD^Va and RhD^Va-like samples in Japanese blood donors. Materials and Methods: Ten RhD^Va samples lacked epD1 and 5 and 3 RhD^Va-like variants also lacked, epD2 and a part of 6/7. We identified the full-length nucleotide sequences of the complementary DNA (cDNA) synthesized from 4 samples: 3 of type D^Va and the 4th a D^Va-like variant. Results: Although their sequences differed from each other, all the substitutions were exclusively in exon 5. Three D^Va samples had hybrid RHD-CE(5)-D alleles, but the D^Va-like variant had a unique nucleotide substitution with a single amino acid change, E233K. Exon 5 of the genomic DNA from all 13 samples was analyzed by sequencing. No other sequences were identified. Conclusion: All RhD^Va and RhD^Va-like variants had the substitution for E233. E233 seems to be a determinant of epD1 and 5. A new category of RhD variant, DYO, was identified.