RHD genotyping in weak D phenotypes by multiple polymerase chain reactions.
BACKGROUND
Weak D phenotypes involve a quantitative variation of D. The genomic basis in weak D has been disputed, however.


METHODS
Five sequence-specific polymerase chain reactions (SSP-PCRs) on exons 2, 5, and 7 of the RHD gene were evaluated in 248 white and 98 Japanese blood donors and compared with the results obtained by amplification of intron 4 and serology. All methods and SSP-PCR testing on the 3' non-coding region of the RHD gene were applied to the genotyping of 94 DNA samples derived from individuals expressing weak D phenotypes.


RESULTS
Concordant results were obtained with all genotyping and phenotyping methods in testing 201 D-positive and 145 D-negative donors. Four of 94 weak D samples were typed as D-negative by amplification of intron 4 and SSP-PCR on exon 5. Phenotyping with monoclonal antibodies revealed a DVI category in one of these cases and DFR phenotype in three of these cases. One weak D sample, which reacted like normal D-positive cells with all applied monoclonal antibodies, was typed falsely negative by SSP-PCR on exon 5 because of a point mutation at nucleotide 667 (T-->G) that resulted in a Phe223Val amino acid substitution. In this individual, heterozygosity was found at two other amino acid positions (Glu233Gln and Val238Met) by restriction fragment length polymorphism analysis.


CONCLUSIONS
Genetic diversity in weak D phenotypes is rare. Only 1 of 90 true weak D phenotypes (1.1%) had a genetic variation in testing on seven gene regions of the RHD gene.
Legler
T J
TJ
Department of Transfusion Medicine, University of Göttingen, Germany.
Maas
J H
JH
Blaschke
V
V
Malekan
M
M
Ohto
H
H
Lynen
R
R
Bustami
N
N
Schwartz
D W
DW
Mayr
W R
WR
Köhler
M
M
Panzer
S
S
D044466:Asian People / Q000235:genetics; D004247:DNA / Q000032:analysis; D005091:Exons; D005838:Genotype; D006801:Humans; D007438:Introns; D010641:Phenotype; D016133:Polymerase Chain Reaction / Q000379:methods*; D018807:Polymorphism, Single-Stranded Conformational; D012204:Rh-Hr Blood-Group System / Q000235:genetics*; D044465:White People / Q000235:genetics
D012204:Rh-Hr Blood-Group System; D004247:DNA