Non-invasive prenatal testing of pregnancies at risk for phenylketonuria

Author(s):  
Huikun Duan ◽  
Ning Liu ◽  
Zhenhua Zhao ◽  
Yiqian Liu ◽  
Yin Wang ◽  
...  

BackgroundPhenylketonuria (PKU) is a common metabolic disorder caused predominately by mutations in the phenylalanine hydroxylase (PAH) gene. The aim of the study was to design and validate the performance of a non-invasive prenatal test (NIPT) for PKU using circulating single molecule amplification and resequencing technology (cSMART).MethodsA total of 18 couples at genetic risk for having a child with PKU were recruited to the study. Gold standard invasive prenatal diagnosis (IPD) was performed on amniocyte or villus cell DNA by Sanger sequencing, targeting the known parental PAH mutations. Retrospectively, NIPT was also performed on stored maternal plasma samples from the 18 pregnancies by a multiplex cSMART assay designed to target all known DNA variants in the PAH gene.ResultsBenchmarking against IPD results, NIPT correctly genotyped all fetuses, including six compound heterozygotes with PKU, four normal non-carriers of PKU and eight heterozygote carriers of PKU comprising five cases of a maternally inherited mutation and three cases of a paternally inherited mutation.ConclusionsThe NIPT cSMART PKU assay was highly sensitive and specific for mutation detection and correct assignment of fetal genotypes. Based on comprehensive mutation coverage across the PAH gene, the assay may initially have clinical utility as a pregnancy screening test for high-risk carrier couples.

Genes ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 26
Author(s):  
Zhaochen Bai ◽  
Hu Zhao ◽  
Shaobin Lin ◽  
Linhuan Huang ◽  
Zhiming He ◽  
...  

As a novel type of genetic marker, the microhaplotype has shown promising potential in forensic research. In the present study, we analyzed maternal plasma cell-free DNA (cfDNA) samples from twin pregnancies to validate microhaplotype-based noninvasive prenatal testing (NIPT) for paternity, zygosity, and fetal fraction (FF). Paternity was determined with the combined use of the relMix package, zygosity was evaluated by examining the presence of informative loci with two fetal genome complements, and FF was assessed through fetal allele ratios. Paternity was determined in 19 twin cases, among which 13 cases were considered dizygotic (DZ) twins based on the presence of 3~10 informative loci and the remaining 6 cases were considered monozygotic (MZ) twins because no informative locus was observed. With the fetal genomic genotypes as a reference, the accuracy of paternity and zygosity determination were confirmed by standard short tandem repeat (STR) analysis. Moreover, the lower FF, higher FF, and combined FF in each DZ plasma sample were closely related to the estimated value. This present preliminary study proposes that microhaplotype-based NIPT is applicable for paternity, zygosity, and FF determination in twin pregnancies, which are expected to be advantageous for both forensic and clinical settings.


2020 ◽  
Vol 40 (8) ◽  
pp. 911-917 ◽  
Author(s):  
Min Pan ◽  
Pingsheng Chen ◽  
Jiafeng Lu ◽  
Zhiyu Liu ◽  
Erteng Jia ◽  
...  

2019 ◽  
Vol 13 (1) ◽  
Author(s):  
Yibo Chen ◽  
Qi Yu ◽  
Xiongying Mao ◽  
Wei Lei ◽  
Miaonan He ◽  
...  

Abstract Background Since the discovery of cell-free DNA (cfDNA) in maternal plasma, it has opened up new approaches for non-invasive prenatal testing. With the development of whole-genome sequencing, small subchromosomal deletions and duplications could be found by NIPT. This study is to review the efficacy of NIPT as a screening test for aneuploidies and CNVs in 42,910 single pregnancies. Methods A total of 42,910 single pregnancies with different clinical features were recruited. The cell-free fetal DNA was directly sequenced. Each of the chromosome aneuploidies and the subchromosomal microdeletions/microduplications of PPV were analyzed. Results A total of 534 pregnancies (1.24%) were abnormal results detected by NIPT, and 403 pregnancies had underwent prenatal diagnosis. The positive predictive value (PPV) for trisomy 21(T21), trisomy 18 (T18), trisomy 13 (T13), sex chromosome aneuploidies (SCAs), and other chromosome aneuploidy was 79.23%, 54.84%, 13.79%, 33.04%, and 9.38% respectively. The PPV for CNVs was 28.99%. The PPV for CNVs ≤ 5 Mb is 20.83%, for within 5–10 Mb 50.00%, for > 10 Mb 27.27% respectively. PPVs of NIPT according to pregnancies characteristics are also different. Conclusion Our data have potential significance in demonstrating the usefulness of NIPT profiling not only for common whole chromosome aneuploidies but also for CNVs. However, this newest method is still in its infancy for CNVs. There is still a need for clinical validation studies with accurate detection rates and false positive rates in clinical practice.


Diagnosis ◽  
2015 ◽  
Vol 2 (3) ◽  
pp. 141-158 ◽  
Author(s):  
Ioanna Kotsopoulou ◽  
Panagiota Tsoplou ◽  
Konstantinos Mavrommatis ◽  
Christos Kroupis

AbstractWith the discovery of existing circulating cell-free fetal DNA (ccffDNA) in maternal plasma and the advent of next-generation sequencing (NGS) technology, there is substantial hope that prenatal diagnosis will become a predominately non-invasive process in the future. At the moment, non-invasive prenatal testing (NIPT) is available for high-risk pregnancies with significant better sensitivity and specificity than the other existing non-invasive methods (biochemical and ultrasonographical). Mainly it is performed by NGS methods in a few commercial labs worldwide. However, it is expected that many other labs will offer analogous services in the future in this fast-growing field with a multiplicity of in-house methods (e.g., epigenetic, etc.). Due to various limitations of the available methods and technologies that are explained in detail in this manuscript, NIPT has not become diagnostic yet and women may still need to undergo risky invasive procedures to verify a positive finding or to secure (or even expand) a negative one. Efforts have already started to make the NIPT technologies more accurate (even at the level of a complete fetal genome) and cheaper and thus more affordable, in order to become diagnostic screening tests for all pregnancies in the near future.


2012 ◽  
Vol 36 (5) ◽  
Author(s):  
Amy Swanson ◽  
Christin Coffeen ◽  
Amy J. Sehnert

AbstractAfter decades of research, non-invasive prenatal testing (NIPT) using maternal blood to determine fetal chromosome status has found its way from the research laboratory into clinical practice, triggering a long-awaited paradigm shift in prenatal care. A variety of methods using sequencing of maternal cell-free DNA (cfDNA) have now been studied, primarily demonstrating their ability to detect the most common fetal aneuploidy, trisomy 21 (T21). The focus of this article is on massively parallel sequencing (MPS) with optimized sequence tag mapping and chromosome quantification, which accurately detects T21 as well as multiple other aneuploidies across the genome. The power of this technique resides in its high precision and reduction of variation within and between sequencing runs. Using MPS, classification of aneuploidy status for a given sample can be reliably assigned from the genetic information alone without the need to factor in other maternal pre-test risk or other clinical variables. Performance of this method has been prospectively demonstrated in a rigorous, blinded, multi-center study in the United States. The findings suggest that MPS can be incorporated into existing prenatal screening algorithms to reduce unnecessary invasive procedures. This technology and key considerations for clinical implementation are discussed.


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