RHC and RHc genotyping in different ethnic groups

BACKGROUND: RH genotyping assays are mainly based on research in whites. These assays may not be reliable in a multiracial society because of the genetic variation in RH among ethnic groups. STUDY DESIGN AND METHODS: Five groups from different ethnic backgrounds were serologically typed for C and c and were genotyped on nucleotide C48 and intron 2 for RHC and RHc on nucleotides C178 and C307. RESULTS: RHc genotyping with both methods proved to be reliable. RHC genotyping on C48 is not reliable because of a 48G>C mutation in the RHce allele (false‐positive prediction of C). This mutation was found in every ethnic group and does not affect c or e expression. RHC genotyping on intron 2 is unreliable because of r′s (Cdes) alleles (a false‐negative prediction of C). This allele was found in whites and blacks from Curaçao and South Africa. Reactions of r′s cells with anti‐C are weaker, but no negative reactions with various MoAbs were found. A new method (RHC/c/hex3‐intron 4/exon 7 multiplex PCRs) was developed based on intron 2 and r′s hybrid exon 3 characteristics (RHC) and C307 (RHc). CONCLUSIONS: Reliable RHC and RHc genotyping is possible in different ethnic groups with the RHC/c/hex3‐intron 4/exon 7 multiplex PCR approach.