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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, RESULTS. Meshes: Adult, Alleles, Amino Acid Substitution, DNA, Complementary, Erythroblastosis, Fetal, Exons, Female, Genotype, Humans, Infant, Newborn, Male, Polymerase Chain Reaction, Polymorphism, Restriction Fragment Length, Polymorphism, Single Nucleotide, Pregnancy, Rh-Hr Blood-Group System, Sequence Analysis, DNA.
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Is the low prevalence Rh antigen Be ( a ) ( Rh36 ) associated with RHCE*ce 662C > G in exon 5 , which is predicted to encode Rhce 221Arg? Context: The low prevalence antigen, Be(a), is produced by a complex that also produces weak c, e and f (ce). We report here the molecular basis associated with Be(a) antigen expression. Peripheral blood samples from four Be(a+) probands were tested. Haemagglutination, gDNA extraction, PCR-based assays, reticulocyte RNA isolation, Rh-cDNA analyses, and sequencing were performed by standard procedures. RBCs from Probands 1 and 3 were D-C-E-c+e+, and from Probands 2 and 4 were D+C+E-c+(W)e+. In proband 1, cDNA sequencing of RHCE revealed heterozygosity of nucleotide (nt) 662C/G in exon 5 of RHCE*ce. No other nucleotide changes were observed. As the 662C>G nucleotide change ablates a MscI restriction enzyme cleavage site, PCR-RFLP analysis was performed and the RHCE*ce nt 662C/G heterozygosity was detected on gDNA from the four probands and two children from both Proband 3 and Proband 4.
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The low prevalence Rh antigen, Be(a), is associated with a single nucleotide change in exon 5 of RHCE*ce; that of 662C>G and this change is predicted to alter proline at amino acid position 221 of Rhce to arginine. The fundamental differences in the properties of these two amino acids may impose a steric and/or charge-related effect on the protein, and thereby provide an explanation for the weakened expression of c, e and f (ce) antigens in the Be(a) phenotype. Final Decision: yes