RHD allele distribution in Africans of Mali

We surveyed the molecular structure and frequency of RHD alleles in Mali (West Africa) by evaluating 116 haplotypes. Only 69% could be attributed to standard RHD (55%) or the RHD deletion (14%). The aberrant RHD allele DAU-0 was predicted for 19%, RHDΨ for 7% and Ccdes for 4% of all haplotypes. DAU-3 and the new RHD allele RHD(L207F), dubbed DMA, were found in one haplotype each. A PCR-RFLP for the detection of the hybrid Rhesus box diagnostic for the RHD deletion in Europeans was false positive in 9 individuals, including all carriers of RHDΨ . Including two silent mutations and the RHD deletion, a total of 9 alleles could be differentiated.Besides standard RHD and the RHD deletion, DAU-0, RHDΨ and Ccdes are major alleles in Mali. Our survey proved that the most frequent alleles of West Africans have been recognized allowing to devise reliable genotyping and phenotyping strategies.The D antigen of the RH blood group (ISBT 004.001; RH1; CD240D; "Rhesus D") is the most important blood group antigen determined by a protein. Anti-D antibodies remain the leading cause for the hemolytic disease of the newborn [1], and antigen D compatible transfusion is standard practice in modern transfusion therapy.Among Europeans, the presence and absence of the antigen D on the red blood cells (RBC) correlates closely with the presence of the "standard" RHD allele and a deletion of the whole RHD gene, respectively. Only about 1% of Europeans carry aberrant RHD alleles encoding variant antigen D [2-4], which may cause typing problems or are permissive to immunization by a normal antigen D.For people of African descent a different scenario emerged: D negative Africans often carry RHD alleles like RHDΨ [5] and Ccdes [6], which harbor large remnants of the RHD gene. Furthermore, some partial D alleles appeared to be quite frequent [7], and anti-D immunizations in D positive individuals were reported to be more frequent than in Europeans [8].Despite the apparent complexity of RHD alleles