Background: The Rhesus antigen Ew (ISBT designation 004 011) was first described in 1955. It is defined by a specific antibody, but its molecular genetic basis has not yet been resolved.
Study design and methods: Two individuals serologically characterized to express the rare Rhesus antigen Ew were analyzed by sequencing of all 10 exons of the RHCE gene.
Results: A nucleotide exchange at position 500 (T500A) resulting in a Met167Lys amino acid substitution was found in both individuals. Moreover, we show that an individual carrying the Ew antigen is capable to produce an alloantibody against the wild-type E antigen.
Conclusion: The single-point mutation T500A in exon 4 of the RHCE gene is a molecular basis of the rare Rhesus antigen Ew.