If a patient has the Rh genotype R1R1, what is their genotype using the Fish-Race nomenclature?

In the context of the Rh blood group system, the R1R1 genotype indicates that the patient inherits the R1 allele (which generally corresponds to DCE) from both parents. According to the Fisher-Race nomenclature, alleles are categorized based on the presence of specific antigens on red blood cells.

For the R1 genotype, it consistently contains the D antigen along with the C and E antigens in a specific configuration. When both alleles are R1, this means that the individual expresses the C and E antigens associated with the D antigen, represented as CDe.

By taking into account that both alleles are identical and correspond to the R1 allele, the valid genotype according to the Fisher-Race nomenclature for R1R1 is indeed CDe/CDe. Therefore, the answer accurately reflects that both alleles contribute the same DCE configuration. This understanding is crucial for proper blood group testing and transfusion compatibility.