Evidence for a 'new' Rh gene complex producing the rare Cx (Rh9) antigen in the Somali population of East Africa.

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.