Polymorphisms of RhDVa and a new RhDVa-like variant found in Japanese individuals

Background and Objectives: Red cell type RhDVa lacks epD1 and 5 and is encoded by hybrid RHD-CE(5)-D alleles. We analyzed RhDVa and RhDVa-like samples in Japanese blood donors. Materials and Methods: Ten RhDVa samples lacked epD1 and 5 and 3 RhDVa-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 RhDVa and RhDVa-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. Copyright (C) 2000 S. Karger AG. Basel.