Objective: To elucidate the molecular background of Del phenotype in the Chinese population and explore new Del alleles.
Methods: Five hundred and fifteen RhD negative blood samples was tested by Rh typing test, indirect antiglobulin test and adsorption and elution assay to screen the Del phenotype. DNA of all the Del samples was analysed by multiplex polymerase chain reaction (MPX PCR) for the presence of RHD and by sequence-specific primer polymerase chain reaction (PCR-SSP) for Del alleles: RHD 1227A and RHD 885T. Samples which showed the negative result by PCR-SSP, were additionally analysed by genomic DNA sequencing and cDNA sequencing.
Results: Seventy-nine Del samples were found by adsorption and elution assay. All these samples had RHD exons 3, 4, 5, 6, 7 and 9. Except 4 Del samples, other 75 Del samples carried the RHD 1227A allele. None of the samples had the RHD 885T allele. Four novel RHD alleles were found in these four Del sample. There were RHD 3G-->A (GenBank DQ310735), RHD 28C-->T, RHD 53T-->C (GenBank DQ451877,DQ451878), RHD 251T-->C (GenBank DQ310734).
Conclusion: fnRh blood group system is very complex. New D variation phenotypes and new RHD alleles may be discovered ceaselessly.