RHD Positive Haplotype in D Negative Omani Blood Donor

The frequency of RhD negative in Omanis is 8.35% but the molecular background explaining this phenotype is unknown in this population. The RhD negative phenotype has a high molecular diversity. We describe a case report of serological D negative with existence of complete RHD gene in an Omani blood donor. Molecular analysis of RHD exons showed duplication across the boundary of intron 3 and exon 4. This is a 37 bp insert in RHD exon 4 along with c.609 G>A mutation. We were uncertain if the presence of RHDΨ is homozygous [RHDΨ./ RHDΨ.] or hemizygous [RHDΨ./del]. Therefore, molecular basis of D zygosity determination would be a good approach to further explore the case.