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Polymorphisms of RhD(Va) and a new RhD(Va)-like variant found in Japanese individuals
H Hyodo1, Y Ishikawa, K Kashiwase
1Japanese Red Cross Central Blood Center, Tokyo, Japan.
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.