<i>RHCE*ceAG</i> (254C&gt;G, Ala85Gly) is prevalent in blacks, encodes a partial ce‐phenotype, and is associated with discordant <i>RHD</i> zygosity

Abstract

BACKGROUND: RHCE*ceAG has the nucleotide change c.254C>G, which encodes p.Ala85Gly associated with altered expression of e antigen. We analyzed serologic and DNA-based testing data on samples with RHCE*ceAG to determine its effect on antigen expression, linkage with RHD, and its prevalence in African Americans. STUDY DESIGN AND METHODS: Serologic testing was performed by standard methods. Genomic DNA was used for polymerase chain reaction-restriction fragment length polymorphism, RH-specific exon sequencing, and RHD zygosity, and Rh-cDNA was sequenced. Samples from 32 individuals referred for serologic problems, 57 patients with sickle cell disease, and 44 donors positive for c.254C>G were investigated. Allele prevalence was determined in random African Americans. RESULTS: Red blood cells from samples homozygous RHCE*ceAG/ceAG or in trans to RHCE*cE reacted variably with anti-e reagents and 17 samples from the 32 referred patients had alloanti-e in their plasma. The majority of samples with RHCE*ceAG, when tested for RHD zygosity gave discordant results between PstI-RFLP and hybrid box assay. Rare samples with 254C>G had additional allelic changes: one with c.697G (p.233Glu), three with c.733G, 941C (p.245Val, 314Ala), and two with c.307T (p.103Ser) encoding robust C antigen expression in the absence of other C-specific nucleotides. A total of 101 samples with RHCE*ceAG were encountered in 1159 randomly selected African Americans. CONCLUSIONS: RHCE*ceAG (c.254G, p.85Gly) encodes a partial phenotype and the absence of the high-prevalence antigen RH59 (CEAG). The allele was present in one in 11 African Americans and is most often in cis to a RHD deletion associated with discordant RHD zygosity. To further determine clinical significance, detection of this allele should be part of routine RHCE genotyping in this population.