Large-scale pre-diagnosis study of fetal RHD genotyping by PCR on plasma DNA from RhD-negative pregnant women.
BACKGROUND
The routine prenatal determination of fetal RhD blood group would be very useful in the management of pregnancies in RhD-negative women, as up to 40% of these pregnancies bear a RhD-negative fetus. The fetal DNA present in maternal plasma offers an opportunity for risk-free prenatal diagnosis.


OBJECTIVE
This study focused on the feasibility and accuracy of large-scale RhD fetal diagnosis in non-immunized and anti-D immunized RhD-negative women.


METHODS
Plasma DNA was extracted from 893 RhD-negative pregnant women and amplified in exons 7 and 10 of the RHD gene using conventional and real-time PCR. The results were then compared with the RHD fetal genotype determined on amniotic cells and/or the RhD phenotype of the red blood cells of the infants at birth.


RESULTS
After exclusion of 42 samples from women exhibiting a nonfunctional or rearranged RHD gene, fetal RhD status was predicted with a 99.5% accuracy. A strategy is also proposed to avoid the small number of false-positive and -negative results.


CONCLUSIONS
Fetal RHD genotyping from maternal plasma DNA in different clinical situations may be used with confidence.
Rouillac-Le Sciellour
Christelle
C
Perinatal Hemobiology National Reference Centre (CNRHP), Hôpital Saint-Antoine, Paris, France. christelle.lesciellour@sat.ap-hop-paris.fr
Puillandre
Philippe
P
Gillot
Rolande
R
Baulard
Céline
C
Métral
Sylvain
S
Le Van Kim
Caroline
C
Cartron
Jean-Pierre
JP
Colin
Yves
Y
Brossard
Yves
Y
D001483:Base Sequence; D004247:DNA / Q000097:blood* / Q000235:genetics*; D003951:Diagnostic Errors; D004899:Erythroblastosis, Fetal / Q000097:blood / Q000175:diagnosis / Q000235:genetics; D005091:Exons; D005260:Female; D005312:Fetal Blood / Q000276:immunology*; D005838:Genotype; D006801:Humans; D007231:Infant, Newborn; D007438:Introns; D008297:Male; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D011296:Prenatal Diagnosis; D012204:Rh-Hr Blood-Group System / Q000235:genetics*
D012204:Rh-Hr Blood-Group System; C026410:Rho(D) antigen; D004247:DNA