OBJECTIVETo explore the molecular basis of 4 cases with weak D variant of Rh blood type.

METHODSRoutine serological testing was applied to determine the D, C, c, E and e antigens of the Rh blood group. The D antigen was further detected with an indirect antiglobulin test. RHD zygosity was detected by sequence-specific primer PCR method. All exons and flanking intron regions of the RHD gene were sequenced.

RESULTSThe samples were determined as weak D phenotype by serological testing. DNA sequencing showed that the 4 cases were heterozygous for 17C>T mutation in exon 1, 29G>C mutation in exon 1, 1212C>A mutation in exon 9, and IVS4+5G>A mutation in intron 4 of the RHD gene, respectively. According to the rule of Rhesus Base Nomenclature, the 4 samples were respectively named as weak D type 31, weak D type 71, weak D type 72, and weak D type 82.

CONCLUSIONSerological and molecular testing for the weak D can facilitate in-depth understanding of its immunology and genetics, and provide guidance for clinical blood transfusion and prevention of hemolytic disease in newborns.