Full text
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| Author(s): |
Daphne Renata Tavares Amaral
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Faculdade de Ciências Médicas |
| Defense date: | 2010-08-30 |
| Examining board members: |
Lilian Maria de Castilho;
Eliana Martorano Amaral;
José Mauro Kutner
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| Advisor: | Lilian Maria de Castilho |
| Abstract | |
Maternal plasma analysis for determination of the fetal RHD status is an important tool for the management of RhD-negative pregnant, specially alloimunized women. We assessed the accuracy of fetal RHD genotyping by analysis of maternal plasma in a multi-ethnic population. We analyzed plasma samples from 88 RhD-negative pregnant women between 11 and 39 weeks of gestation, median age of 28 years old to determine the fetal RHD genotype. This population was from Southeastern Brazil with high mixed ethnic background. Thirteen patients (14,78%) had anti-D alloantibody. We used TaqMan primers and probes to detect exons 4, 5 and 10 of RHD, by real-time PCR. As internal controls, we used primers/probes sets to SRY and CCR5. Peripheral or umbilical cord bloods from respective neonates were collected during delivery and hemagglutination was performed. Conventional RHD genotyping was realized in all pregnant. Eighty-three patients had a deletion of RHD gene and five samples were identified RHD variants (3 RHD and 2 DFR). The conventional RHD genotyping was also performed on 17 DNA samples from fathers. Fifteen samples were genotyped as RHD+ (5 RHD+/RHD+ and 10 RHD+/RHD-) and 2 RHD-negative. Fifty-eight (65,91%) fetuses were genotyped as RHD+. Twenty-seven (30,68%) samples showed completely absence of RHD and three fetuses showed amplification only for the exon 10, demonstrating the presence of a possible variant (RHD or RHD-CE-Ds). All fetal RHD results agreed with the neonatal typing including the 3 fetuses with RHD variant, phenotyped as RhD-negative. Thus, the accuracy of the fetal RHD genotyping in this population was 100%. The earliest pregnancy in which fetal RHD was detected was 11 weeks. Our findings indicate that the accuracy of fetal RHD genotyping from maternal plasma using 3 regions (exons 4, 5 and 10) can be sufficient for clinical application in a multi-ethnic population. This knowledge helped us on the development of a feasible protocol for fetal RHD genotyping on DNA from maternal plasma in our population and should become practice in the near future (AU) | |
| FAPESP's process: | 07/07151-3 - FETAL RHD GENOTYPING FROM MATERNAL PLASMA BY USING REAL TIME PCR |
| Grantee: | Daphne Renata Tavares Amaral |
| Support Opportunities: | Scholarships in Brazil - Master |