Fetal rhd genotyping from maternal plasma in a population with a highly diverse ethnic background.
OBJECTIVE
To establish the performance of conventional PCR as a noninvasive method for fetal genotyping, by free fetal DNA analysis of distinct RHD regions from maternal plasma, in a population of a diverse ethnic origin.


METHODS
We conducted a validity of the diagnostic test by analyzing 81 plasma samples from RhD-negative Brazilian pregnant women, from 4 to 41 gestational weeks. We tested for exon 10 and intron 4 gene regions by allele specific-PCR. Fetal RHD genotyping by PCR on maternal plasma was compared to serologic RhD typing in the neonatal period.


RESULTS
Samples were obtained as follows: 15 in the 1st, 37 in the 2nd and 29 in the 3rd trimester. General accuracy was 97.3%, sensitivity of 98.3% and specificity of 93.8%.


CONCLUSIONS
Conventional PCR is an accurate method for fetal RHD genotyping on maternal plasma, even in a population of mixed ethnic origin.
Machado
Isabela Nelly
IN
Departamento de Tocoginecologia da Universidade Estadual de Campinas e Hemocentro Unicamp, Universidade Estadual de Campinas, Campinas, SP. imachado@fcm.unicamp.br
Castilho
Lilian
L
Pellegrino
Jordão
J
Barini
Ricardo
R
D001938:Brazil; D004247:DNA / Q000097:blood* / Q000302:isolation & purification; D004587:Electrophoresis, Agar Gel; D005006:Ethnicity; D005091:Exons; D005260:Female; D005312:Fetal Blood / Q000276:immunology; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D016133:Polymerase Chain Reaction / Q000592:standards*; D011247:Pregnancy; D011264:Pregnancy Trimesters; D011296:Prenatal Diagnosis / Q000379:methods*; D012204:Rh-Hr Blood-Group System / Q000097:blood / Q000235:genetics*; D012680:Sensitivity and Specificity
D012204:Rh-Hr Blood-Group System; C026410:Rho(D) antigen; D004247:DNA