Evidence for a ‘new’ Rh gene complex producing the rare C^x (Rh9) antigen in the Somali population of East Africa

Abstract

Four unrelated propositi with an unusual Cx-positive Rh phenotype were found during a population survey of 513 Somalis. The Rh phenotypes of the propositi and their available relatives showed that the gene that produces the Cx antigen differs from that found in whites in that it is inherited with an Rh gene complex that produces no C or D. Instead, this gene complex produced es, c, and probably V, although it appeared that no f (ce) antigen was made. These findings suggest that Cx cannot be considered a simple variant form of C but rather a distinct rare Rh antigen that may occur in association with different Rh gene complexes.

MAR, a Novel High‐Incidence Rh Antigen Revealing the Existence of an Allelic Sub‐System Including Cw (Rh8) and Cx (Rh9) with Exceptional Distribution in the Finnish Population

“…associated only with the DCe complex in Caucasians, it occurs with a relatively high 1% frequency in the East-African Somalis [8]. In this population, the antigen c" is produced by a native African gene complex dces [9]. The association is thus very different from that found in Caucasians.…”

On the trail of anti‐CDE to unexpected highlights of the RHD*weak 4.3 allele in the Upper Austrian population

“…In two samples with D+C‐c+E+e+ phenotype, a suppressed expression of the e antigen on RBCs was noted. This altered expression was identified before when associated with C X [19, 24] but also with Cys16 and VS [3, 19]. In the other samples with the e‐specific nucleotides in homozygous occurrence, a depressed expression of e S was not detected, explainable by masking of the aberrant haplotype by the conventional Rhe encoded on the partner chromosome.…”

“…Subsequent RHCE ‐specific nucleotide sequencing revealed three alterations: 48 G>C, 106 G>A and 733 C>G leading to W16C, A36T and L245V amino acid substitutions. The L245V mutation is known as VS antigen expressing ce S [3, 16–18], while the A36T substitution was characterized as C X before [19]. Molecular analysis of 27 blood donor samples known to harbour the RHD*weak 4.3 allele revealed identical results.…”

“…RHce(L245V) is responsible for the presence of the VS antigen and expresses e S . Its occurrence is typical for African populations and was determined with a frequency of up to 50% in African descendants [3, 18, 19, 23]. Daniels and co‐workers considered a selective advantage of Val245 in Africa [3].…”

MAR, a Novel High-Incidence Rh Antigen Revealing the Existence of an Allelic Sub-System Including C^w (Rh8) and C^x (Rh9) with Exceptional Distribution in the Finnish Population

“…associated only with the DCe complex in Caucasians, it occurs with a relatively high 1% frequency in the EastAfrican Somalis [8]. In this population, the antigen Cx is produced by a native African gene complex dee' [9]. The association is thus very different from that found in Cau casians.…”