From the following phenotype Anti-D +, Anti-C +, Anti-E 0, Anti-c +, Anti-e +, what is the most common genotype?

From the following phenotype Anti-D +, Anti-C +, Anti-E 0, Anti-c +, Anti-e +, what is the most common genotype?

• A. R^1r
• B. rr
• C. dCE/dCE
• D. CDE/cde

Answer: (A)

Rh inheritance uses two Rh haplotypes on each person’s two chromosomes. The phenotype described shows D and C antigens present, E absent, and both c and e antigens present. The common pairing that yields this pattern is one chromosome with the DCe haplotype (R1) and the other with the dce haplotype (r). That combination gives D+, C+, E−, c+, e+. So the most typical genotype is R1r. Homozygous rr would lack D, so not D+. A dCE/dCE or a CDE/cde pairing would introduce E antigen on both chromosomes, not match the E− result.

Rh inheritance uses two Rh haplotypes on each person’s two chromosomes. The phenotype described shows D and C antigens present, E absent, and both c and e antigens present. The common pairing that yields this pattern is one chromosome with the DCe haplotype (R1) and the other with the dce haplotype (r). That combination gives D+, C+, E−, c+, e+. So the most typical genotype is R1r.

Homozygous rr would lack D, so not D+. A dCE/dCE or a CDE/cde pairing would introduce E antigen on both chromosomes, not match the E− result.