RHD*509G Allele Associated with an RhD Variant Phenotype: A Case Report

This study aims to investigate an unusual RhD variant phenotype in a pregnant Chinese woman. Serological methods were utilized to confirm RhD-negative status, perform CE serotyping, and screen for unexpected antibodies in a pregnant woman who was initially identified as D-negative. RHD gene-coding regions were amplified and sequenced, and RHD zygosity was also detected using PCR. The impact of an identified missense mutation was predicted using MutationTaster software. The case was identified serologically as a weak D phenotype with a CE type of Ccee. No unexpected antibodies were detected. The hybrid Rhesus box was identified as RHD⁺/RHD⁻ heterozygote, and the haplotype was hypothesized to be CD^we/cde. The sequencing results revealed a novel missense mutation, c.509T>G, in exon 4 of RHD gene, leading to the amino acid change p. Met170Arg. Allele RHD*509G was found to be a new RhD variant, and the sequence was submitted to GenBank under accession number MW923730.