Genotipagem RHD fetal atraves da analise do plasma materno

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

Hemolytic Disease of the Fetus and Newborn still contributes to perinatal morbidity and mortality, in spite of the widespread munoprophylaxis. Prenatal identification of fetal RHD status is a goal of obstetrical practice, in order to prevent maternal immunization and to help in the management of alloimmunized pregnant women. The analysis of the maternal plasma opened up new posibilities for noninvasive prenatal diagnosis and the determination of fetal RHD genotype is one of the most relevant application of this molecular analysis. Objective: To establish the performance of conventional PCR analysis of the maternal plasma as a method to genotype fetal RHD. Method: A validity of diagnostic test was conduced with 81 peripheral blood samples obtained from RhD-negative pregnant women, between 4 and 41 weeks of gestation. Commercially available kits were used to extract DNA from the maternal plasma. Exon 10 and intron 4 RHD gene regions were tested using conventional Allele-Specific Polymerase Chain Reaction (AS-PCR). Fetal RHD genotyping by PCR on maternal plasma was compared to conventional Rh typing in neonatal period and data analysed by SAS- 8.2 version@ (1999-2001). Results: Samples were obtained as follows: 15 on 1 si, 37 on 2nd and 29 on 3rd trimester. Amplification failed in six of the specimens, 3 were RhD-negative and 3 RhD-positive at neonatal typing. Concordance between the genotyping and neonatal typing was 97.3%, sensitivity of 98.3% and specificity of 93.8%. One false positive in the third trimester and one false negative in the first trimester were observed. Conclusion: Conventional AS-PCR is an accurate method for fetal RHD genotyping on maternal plasma, as a noninvasive prenatal dignosis.

ASSUNTO(S)

diagnostico pre-natal

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