Detection of fetal RHD pseudogene (RHDΨ) and hybrid RHD-CE-Ds from RHD-negative pregnant women with a free DNA fetal kit

Günel, Tuba; Kalelioğlu, I.; Gedikbaşı, Ali; Ermiş, Hayri; Aydınlı, Kılıç

doi:10.4238/2011.october.26.1

Cited by 5 publications

(5 citation statements)

References 16 publications

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“…In the Caucasian population deletion of homozygous RhD gene is the main cause of negative phenotype in contrast with black Africans who do not have homozygous deletion but carry one or two variant genes, the RhD pseudogene or RHD-CE-Ds hybrid gene. [13,14] [12,15,16] Multiplex PCR for more than one region should be performed to detect this hybrid or pseudogenes [16]. The present authors performed only exon 7 in this study, not exon 10 therefore one patient with a false positive result may have pseudogene.…”

Section: Discussionmentioning

confidence: 94%

Non-invasive prenatal diagnosis of fetal RhD by using free fetal DNA

Gönenç¹,

İşçi²,

Yiğiter³

et al. 2015

Clin. Exp. Obstet. Gynecol.

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Objective: Anti-D immunoglobulin is applied to all pregnant women having RhD incompatibility to prevent hemolytic disease of the newborn. The aim of this study is to determine fetal RhD status in the Rh incompatible pregnancies with an non-invasive technique; free fetal DNA isolation from maternal circulation. In the case of Rh incompatibility especially with a history of previous fetal anemia, it can be beneficial to know Rh status antenatally in terms of monitoring fetuses with Rh positive [RhD(+)] status consciously. Materials and Methods: Total free DNA was isolated in 50 Rh negative [RhD(−)] pregnant women, who had RhD alloimmunisation with their husbands. The gene in isolated DNA was investigated with TagMan prob and real time PCR by using primers belonging to exon 7 of the RhD gene. Results: The authors analyzed 50 RhD(−) women by using quantitative real time PCR technique. Five of them were RhD(−) and the rest of them were found to be RhD(+). After birth one of the infants who were analyzed as RhD(+) were found to be RhD(−). Conclusion: The detection of fetal RhD status by using a non-invasive method from maternal circulation was found to be possible. Assessing fetal RhD status non-invasively by using free fetal DNA in maternal blood will be cost-efficient, avoiding unnecessary indirect Coombs test and unnecessary Rhogam applications that is used in RH incompatible pregnancies. This study will throw a fresh light on prenatal diagnosis.

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Section: Discussionmentioning

confidence: 94%

Non-invasive prenatal diagnosis of fetal RhD by using free fetal DNA

Gönenç¹,

İşçi²,

Yiğiter³

et al. 2015

Clin. Exp. Obstet. Gynecol.

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“…This approach was also recommended by other authors [2,24], who suggested including exons 4 or 5 and exons 7 or 10 so as to avoid wrong fetal RHD genotyping due to rare Rh blood group polymorphisms [25]. These exons depend on different mutations or DNA sequence exchanges between RHD and RHCE , the two homologous genes that are responsible for the RhD phenotype.…”

Section: Discussionmentioning

confidence: 99%

Non-Invasive Prenatal <b><i>RHD</i></b> Genotyping Using Cell-Free Fetal DNA from Maternal Plasma: An Italian Experience

Picchiassi

Renzo

Tarquini

et al. 2014

Transfus Med Hemother

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Background: This study assessed the diagnostic accuracy of a non-invasive approach to fetal RHD genotyping using cell-free fetal DNA in maternal plasma and a combination of methodological strategies. Methods: Real-time PCR (qPCR) was performed on 216 RhD-negative women between weeks 10+0 and 14+6 of gestation (1st qPCR). qPCR was repeated (2nd qPCR) to increase the amount of each sample for analysis, on 95 plasma aliquots that were available from first trimester blood collection (group 1) and on 13 samples that were collected between weeks 18+0 and 25+6 of gestation (group 2). qPCR was specific for exons 5 and 7 of the RHD gene (RHD5 and RHD7). The results were interpreted according to the number of positive replicates of both exons. Results: 1st qPCR: diagnostic accuracy was of 93.3%. Diagnostic accuracy increased from 90.5% (1st qPCR) to 93.7% (2nd qPCR) in group 1 and from 84.6% (1st qPCR) to 92.3% (2nd qPCR) in group 2. These increments were not statistically significant. Conclusion: Our approach to RHD genotyping in early pregnancy yielded high diagnostic accuracy. Increasing the amount of DNA analyzed in each sample did not improve significantly the diagnostic accuracy of the test.

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“…RHD (del Ex8) and RHD (del Ex9) alleles are classified as long deletions of the RHD gene [26,28], and RHD (del Ex9) is now determined to be nonexistent but resulted from a misinterpretation of data on RHD (1,227G>A) [12,27]. RHD-CE(4-9)-D belongs to RHD-CE-D hybrid gene [14,30,31,32]. Körmöczi and colleagues [9] proposed that DEL phenotypes should be divided into two subtypes: complete types where the majority of epDs are conserved such as RHD (1,227G>A) and partial D-like variants with characteristic epD loss caused by either RHD-CE-D hybrid genes or RHD point mutations RHD (IVS3 + 1G>A) affecting extracellular RhD loops.…”

Section: Discussionmentioning

confidence: 99%

Prospective Evaluation of a Transfusion Policy of RhD-Positive Red Blood Cells into DEL Patients in China

Wang

Zhu

Wang

et al. 2015

Transfus Med Hemother

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Background: The D antigen is highly immunogenic, requiring only a small quantity of transfused red blood cells (RBCs) to cause alloimmunization in D- immunocompetent recipients. DEL was reported arousing alloimmunization to true Rh- patients. Molecular studies of the RHD gene have revealed that DEL individuals retain a grossly intact RHD gene or have a portion of RHD in their genomes. Avoiding immunization with clinically important antibodies is a primary objective in transfusion medicine. Methods: In order to determine whether pregnant DEL women carrying an RhD+ fetus are at risk of anti-D alloimmunization, 808 Rh- pregnant women with a history of gestations or parturitions who regularly visited hospitals for their prenatal anti-D screening and postpartum care from January 2011 to December 2012 were investigated. Samples were analyzed for DEL by PCR with specific primers, PCR-sequence-specific primers (PCR-SSP), reverse transcription-PCR (RT-PCR), PCR-restriction fragment length polymorphism (PCR-RFLP), and by gene sequencing to characterize different alleles. Results: Among the 808 Rh- pregnant women of our sample, 178 (22.0%) were typed as DEL; 168 DEL samples were confirmed to have the RHD (1,227 G>A) allele, 8 DEL samples were characterized by one base mutation of the RHD (3G >A) allele, and the remaining two DEL samples were determined to carry RHD-CE(4-9)-D or RHD-CE(2-5)-D. The observation of allo-anti-D in two prominent D epitope loss cases confirmed the partial nature of these DEL phenotypes. Conclusions: In conclusion, evidence is provided that different DEL genotypes code either for partial or complete D antigen expression. It is suggested that the use of RhD+ RBCs in complete D antigen DEL patients does not induce adverse reaction.

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Detection of fetal RHD pseudogene (RHDΨ) and hybrid RHD-CE-Ds from RHD-negative pregnant women with a free DNA fetal kit

Cited by 5 publications

References 16 publications

Non-invasive prenatal diagnosis of fetal RhD by using free fetal DNA

Non-invasive prenatal diagnosis of fetal RhD by using free fetal DNA

Non-Invasive Prenatal <b><i>RHD</i></b> Genotyping Using Cell-Free Fetal DNA from Maternal Plasma: An Italian Experience

Prospective Evaluation of a Transfusion Policy of RhD-Positive Red Blood Cells into DEL Patients in China

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