Background: RHD alleles are considered more variable in African persons than in European persons. A systematic survey, however, was lacking among D+ European persons at the molecular level, precluding any definite frequency estimate.
Study design and methods: A random survey was performed among 500 ccDee, 250 CcDee, and 250 ccDEe blood donors in southwestern Germany. They were tested by polymerase chain reaction with sequence-specific priming (PCR-SSP) for up to 12 single-nucleotide polymorphisms representative for the most frequent RHD alleles among European persons. The RHD exon 5 nucleotide sequence was also tested in all 1000 samples. The nucleotide sequence of the 10 RHD exons was checked in all samples with aberrant exon 5 or positive PCR-SSP procedures.
Results: By PCR-SSP, 15 aberrant RHD alleles were found among the 500 ccDee, 2 among the 250 CcDee, and none among the ccDEe samples. One of these was the novel RHD(F223V, E233Q, T379M) allele dubbed DAU-5. Weak D type 4 was detected more frequently than expected, whereas the population frequencies of the other RHD alleles conformed to published estimates. Nucleotide sequencing of RHD exon 5 further revealed three novel alleles RHD(G212G), RHD(R234W), and RHD(V245L), dubbed DUC-1, DQC, and DUC-2.
Conclusion: In a limited screen at the molecular level among 1000 random D+ donors in southwestern Germany, 20 donors were found carrying aberrant RHD alleles. Four of these alleles were new and likely sporadic. An estimate was derived of the variety that may be encountered in genotyping approaches, and it was concluded that even within the European population the variety of RHD alleles may be larger than anticipated.