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 (Cde(s)) alleles (a false-negative prediction of C). This allele was found in whites and blacks from Curacao 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.