The Serological Profile and Molecular Basis of a New Partial D Phenotype, DHR
Background and objectives: The Rh D antigen comprises a mosaic of at least 30 epitopes expressed on a 30-kD non-glycosylated Rh D polypeptide. The equivalent Rh CeEe polypeptide expressing the Rh C/c and E/e antigens differs in only 36 of the 417 amino acid residues. Partial D individuals have been...
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Published in | Vox sanguinis Vol. 73; no. 4; pp. 252 - 256 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
Basel, Switzerland
01.04.1997
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Subjects | |
Online Access | Get full text |
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Summary: | Background and objectives: The Rh D antigen comprises a mosaic of at least
30 epitopes expressed on a 30-kD non-glycosylated Rh D polypeptide. The
equivalent Rh CeEe polypeptide expressing the Rh C/c and E/e antigens differs
in only 36 of the 417 amino acid residues. Partial D individuals have been described
who fail to express a number of D epitopes. Materials and methods:
Serologic methods were applied with monoclonal anti-D to map epitopes on the
red cells of a proposita aberrant D typing. Polymerase chain reaction (PCR) and
DNA sequencing were also done. Results: DNA sequence analysis derived by
RT-PCR using total RNA isolated from peripheral blood of this person suggests
two mechanisms for the genetic basis of this variants: one where gene conversion
events result in the replacement of RHD gene exons with the equivalent RHCE
exons; the second where point mutation in the RFID gene generates an amino acid
substitution in the Rh D protein. Conclusions: We report here a new partial D,
DHR, where a single point mutation (G to A at nucleotide 686) in exon 5 of the
RHD gene results in a conservative amino acid substitution (Arg229Lys), in the
predicted Rh D protein. This residue is localised on the fourth predicted exofacial
loop of the Rh D polypeptide as determined by hydropathy analysis. This substitution
results in the lack of epD 1,2,12 and 20(30 epitope model) and indicates
the involvement of loop 4, and in particular the requirement of Arg(229), in the
expression of these epitopes. |
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ISSN: | 0042-9007 1423-0410 |
DOI: | 10.1159/000461941 |