scholarly journals Discordant structural chromosomal aberrations in chorionic villi and amniotic fluid leading to a formation of an isochromosome 21: a case report

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Eini Westenius ◽  
Maria Pettersson ◽  
Erik Björck

Abstract Background Fetoplacental discrepancies occur in approximately 1–2% of analyzed prenatal cases. They are typically due to confined placental mosaicism, where an aberration is observed in the placental cells but not found in the fetal cells. Confined placental mosaicism usually involves aneuploidies and more sparsely structural chromosomal aberrations. To the best of our knowledge, this is the first reported case of a discrepancy in the analyses of chorionic villus sampling and amniocentesis involving two different structural chromosomal aberrations of chromosome 21. Case presentation We report a 33-year-old woman who was referred for a non-invasive prenatal testing due to an increased risk of trisomy 21 gleaned from a combined ultrasound and blood test. The non-invasive prenatal testing showed an increased risk of trisomy 21 with a normalized coverage signal that did not match the fetal cell-free DNA fraction. Rapid aneuploidy detection performed on uncultured chorionic villi indicated mosaicism for trisomy 21. The follow-up analyses revealed discordant chromosomal aberrations: 46,XY,der(21)t(10;21)(p11.21;q10) in the analysis of the chorionic villus sampling and 46,XY, + 21,der(21;21)(q10;q10) in the analysis of the amniocentesis. Thus, the analyses indicated mosaicism for a cell line containing trisomy 21 and a cell line containing a partially duplicated short arm of chromosome 10 in the chorionic villi and complete trisomy 21 resulting from an isochromosome 21 in the amniotic fluid. The analyses of the lymphocytes and the fibroblasts of the woman were normal. Conclusions We propose a multiple-step mechanism as a possible theoretical explanation for the formation of these discordant structural chromosomal aberrations in the chorionic villi and amniotic fluid. With this case report, we want to highlight the importance of understanding the possible underlying embryological mechanisms when interpreting results from different prenatal analyses.

Author(s):  
Margit Rosner ◽  
Thomas Kolbe ◽  
Viktor Voronin ◽  
Markus Hengstschläger

AbstractCell-free fetal DNA (cffDNA)-based non-invasive prenatal testing (NIPT) is considered to be a very promising screening tool for pregnant women with an increased risk of fetal aneuploidy. Already millions of women worldwide underwent NIPT. However, due to the observed false-positive and false-negative results, this screening approach does not fulfil the criteria of a diagnostic test. Accordingly, positive results still require risk-carrying invasive prenatal testing, such as amniocentesis or chorionic villus sampling (CVS), for confirmation. Such hurdles need to be overcome before NIPT could become a diagnostic approach widely used in the general population. Here we discuss new evidence that besides the placenta amniotic fluid stem cells (AFSCs) could also represent an origin of cffDNA in the mother’s blood. A comprehensive picture of the involved cell source repertoire could pave the way to more reliable interpretations of NIPT results and ameliorate counselling of advice-seeking patients. Graphical abstract


2021 ◽  
Author(s):  
Giuseppina Campisciano ◽  
Mariachiara Quadrifoglio ◽  
Manola Comar ◽  
Francesco De Seta ◽  
Nunzia Zanotta ◽  
...  

The sterile-womb dogma in uncomplicated pregnancy has been lively debated. Data regarding the in utero microbiome environment are based mainly on studies performed at the time of delivery. Aim: To determine whether human placenta and amniotic fluid are populated by a bacterial microbiota in the first and second trimesters of pregnancy. Materials & methods: We analyzed by next-generation sequencing method 24 and 29 samples from chorionic villus sampling (CVS) and amniocentesis (AC), respectively. The V3 region of the 16S rRNA gene was sequenced. Results: 37.5% of CVS and 14% of AC samples showed the presence of bacterial DNA. Conclusion: Our study suggests that bacterial DNA can be identified in the placenta and amniotic fluid during early prenatal life.


2015 ◽  
Vol 38 (4) ◽  
pp. 254-261 ◽  
Author(s):  
Asma Khalil ◽  
Negar Mahmoodian ◽  
Abhijit Kulkarni ◽  
Tessa Homfray ◽  
Aris Papageorghiou ◽  
...  

Objectives: The aim was to investigate aneuploidy detection using an approach based on nuchal translucency (NT) and non-invasive prenatal testing (NIPT). Methods: This was a cohort study including 5,306 high-risk pregnancies with NT measurements and chorionic villus samples (CVS) tested for full karyotype. Results: The fetal karyotype was normal in 4,172 (78.6%) cases and abnormal in 1,134 (21.4%), including 1,009 with a likely clinically significant adverse outcome. Universal CVS with full karyotyping would lead to the diagnosis of all clinically significant abnormalities. A policy of relying solely on NIPT would have led to the diagnosis of 88.9% of clinically significant abnormalities. A strategy whereby NIPT is the main method, with CVS reserved for cases with NT ≥3.0 mm, would require CVS in 21.7% of cases, identify 94.8% of significant abnormalities and avoid miscarriage in 41 pregnancies compared to CVS for all. Conclusions: A policy of NIPT for increased-risk cases and CVS with full karyotype if the NT was ≥3.0 mm reduced the risk of miscarriage yet still identified 95% of clinically significant aneuploidy.


Author(s):  
Abhijeet Kumar ◽  
Madhusudan Dey ◽  
Devendra Arora

<p>Prenatal screening for chromosomal abnormalities has two components i.e. prenatal screening (maternal serum screening and cell-free fetal DNA screening) and prenatal diagnosis (chorionic villus sampling, amniocentesis, and cordocentesis). Prenatal testing in the past decade is evolving towards non-invasive methods to determine the chromosome abnormality disorders in the fetus without incurring the risk of miscarriage. Conventional tools for prenatal screening included maternal age, maternal serum markers, ultrasound marker (nuchal thickness), and their combinations. With the increased risk of screening test patients were offered diagnostic tests (chorionic villus sampling, amniocentesis, and cordocentesis). After the availability of noninvasive prenatal tests for commercial use in 2011, a great marketing drive is there to establish it as a master tool for prenatal testing. However various society guidelines i.e. ACOG, RCOG, and ISUOG have clearly stated that cell-free fetal DNA based noninvasive prenatal tests is a screening test, not a diagnostic test. In the succeeding paragraph, we will review current trends in the field of cell-free fetal DNA noninvasive prenatal tests and the relevance of invasive testing in the context of noninvasive prenatal tests. Noninvasive prenatal tests does not entirely replace invasive prenatal testing procedures. Positive noninvasive prenatal tests findings must be confirmed by diagnostic tests based on an invasive sample source, mainly chorionic villus sampling or amniocentesis due to false positive and false negative reports of cell-free fetal DNA based tests. Continuing research and development efforts are focused on overriding noninvasive prenatal tests limitations. Recent studies show that procedure-associated risks in the case of prenatal invasive testing are very low as compared to previous studies. Prenatal invasive testing will remain as the backbone of prenatal diagnostic testing until the limitation of noninvasive prenatal tests is overcome.</p>


Author(s):  
Kajal Nandi ◽  
Rashmi Verma ◽  
Rajni Dawar ◽  
Binita Goswami

AbstractCell free DNA (cf-DNA) refers to all non -ncapsulated DNA present in the blood stream which may originate from apoptotic cells as a part of the physiological cell turnover, or from cancer cells or fetal cells. Recent studies have highlighted the utility of cfDNA analysis for genetic profiling of cancer, non-invasive prenatal testing besides many other clinical applications. In our review we discuss the sources of cfDNA in the body, the techniques most commonly being used for its isolation and analysis, the applications of cfDNA testing and the associated pros-cons. We conclude that for prenatal testing, cfDNA analysis provides an effective, non-invasive and safer alternative to traditional amniocentesis and chorionic villus sampling tests. Also, in cancer patients, cfDNA analysis is useful for genetic profiling and follow-up during treatment. However, standardization of methods of isolation and analysis has become crucial for the success of widespread use of cfDNA analysis.


2019 ◽  
Vol 2 (1) ◽  
pp. 59-61
Author(s):  
Cristina Moisei ◽  
Anca Lesnica ◽  
Romina Marina Sima ◽  
Liana Pleș

Nuchal translucency (NT) is the normal fluid filled subcutaneous space measured at the back of the fetal neck measured in the late first trimester and early second trimester. Nuchal translucency screening can detect approximately 80% of fetuses with Down syndrome and other major aneuploidies with a rate of 5% of false positive results, but the merger of the NT screening with β-hCG and PAPP-A testing increases the detection rate to 90%. We present the case of a fetus with a NT of 49 mm detected at the first trimester ultrasound morphologic exam. The Kryptor test revealed a 1:35 risk for Trisomy 13 and 1:721 for Trisomy 18. We report the case of an investigated pregnancy with a NT of 49 mm detected at the first trimester ultrasound exam, with a risk of 1:35 for Trisomy 13 and 1:721 for Trisomy 18 calculated at the Kryptor test. A chorionic villus sampling was recommended and performed with a result of 46XY normal karyotype. The particularity of this case is represented by the increased nuchal translucency as well as an increased risk for trisomy 13 and 18 in a normal karyotype fetus that had a normal development in the second and third trimester with no pregnancy complications arising.


2012 ◽  
Vol 15 (Supplement) ◽  
pp. 17-26 ◽  
Author(s):  
Neil D. Avent ◽  
A Webb ◽  
TE Madgett ◽  
T Miran ◽  
K Sillence ◽  
...  

ABSTRACT Current invasive procedures [amniocentesis and chorionic villus sampling (CVS)] pose a risk to mother and fetus and such diagnostic procedures are available only to high risk pregnancies limiting aneuploidy detection rate. This review seeks to highlight the necessity of investing in non invasive prenatal diagnosis (NIPD) and how NIPD would improve patient safety and detection rate as well as allowing detection earlier in pregnancy. Non invasive prenatal diagnosis can take either a proteomics approach or nucleic acid-based approach; this review focuses on the latter. Since the discovery of cell free fetal DNA (cffDNA) and fetal RNA in maternal plasma, procedures have been developed for detection for monogenic traits and for some have become well established (e.g., RHD blood group status). However, NIPD of aneuploidies remains technically challenging. This review examines currently published literature evaluating techniques and approaches that have been suggested and developed for aneuploidy detection, highlighting their advantages and limitations and areas for further research.


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