title: Noninvasive fetal RHD genotyping from maternal plasma in an admixed Brazilian population.
abstract: We evaluated the efficacy of noninvasive fetal Rhesus D (RHD) genotyping from maternal plasma in a highly admixed population. Fifty-five blood samples from RhD-negative pregnant women from Brazil were processed for extraction of cell-free plasma DNA. Real-time PCR was performed to amplify segments of exons 5 and 7 from the RHD gene, as well as for detection of the SRY gene to confirm the presence of fetal DNA. Fetal genotyping results were compared with the RhD phenotype determined from newborn cord blood samples obtained at birth. Thirty-two samples were RHD-positive, 18 were RHD-negative and 5 were inconclusive due to amplification of only one RHD exon. In 43 samples, the fetal RHD genotype was compared to the neonatal RhD phenotype, and only one result was discordant, due to false-negative serology. There was one false SRY genotyping negative result. We conclude that noninvasive fetal RHD genotyping from maternal blood provides accurate results and suggests its viability as a clinical tool for the management of RhD-negative pregnant women in an admixed population.
authors.affiliation: Departamento de Imunohematologia, Fundação Hemominas, Belo Horizonte, MG, Brasil luciana.cayres@hemominas.mg.gov.br.
authors.forename: L C
authors.initials: LC
authors.lastname: Schmidt
authors.affiliation: Centro de Medicina Fetal, Departamento de Obstetrícia e Ginecologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil.
authors.forename: A C V
authors.initials: AC
authors.lastname: Cabral
authors.affiliation: Departamento de Pesquisa, Fundação Hemominas, Belo Horizonte, MG, Brasil.
authors.forename: M A
authors.initials: MA
authors.lastname: Faria
authors.affiliation: Centro de Medicina Fetal, Departamento de Obstetrícia e Ginecologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil.
authors.forename: F
authors.initials: F
authors.lastname: Monken
authors.affiliation: Departamento de Biologia Geral, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil.
authors.forename: E
authors.initials: E
authors.lastname: Tarazona-Santos
authors.affiliation: Departamento de Pesquisa, Fundação Hemominas, Belo Horizonte, MG, Brasil.
authors.forename: M L
authors.initials: ML
authors.lastname: Martins
mesh_terms: D001938:Brazil; D005260:Female; D005333:Fetus; D005838:Genotype; D006801:Humans; D007231:Infant, Newborn; D033261:Maternal-Fetal Relations; D011247:Pregnancy; D011296:Prenatal Diagnosis; D012204:Rh-Hr Blood-Group System / Q000097:blood* / Q000235:genetics
chemical_list: D012204:Rh-Hr Blood-Group System; C026410:Rho(D) antigen