A case of placental trisomy 18 mosaicism causing a false negative NIPT result. Langlois S, Brock J-A, Douglas Wilson R, et al. In the vast majority of pregnancies, although the genetic component between the placental and fetal tissue is identical, false positive or false negative results still exist due to confined placental mosaicism (CPM) [7, 8]. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Furthermore, at 15GA, the fetal DNA percentage was 7.8% due to the mosaicism, and the effective/perceived fetal fraction observed by the algorithm on the trisomy chromosome was (100%–42%)*7.8% = 4.52%. Google Scholar. Liao GJW, Gronowski AM, Zhao Z. Non-invasive prenatal testing using cell-free fetal DNA in maternal circulation. I didn't hear a word he was saying. The waiting is excruciating but eventually you will get an answer. As routine practice, ultrasound was conducted to monitor the developmental status of the fetus. Noninvasive prenatal diagnosis of common aneuploidies by semiconductor sequencing. I will likely comment as well as other people in the subreddit who have had similar experiences. Choi H, Lau TK, Jiang FM, et al. Combined GC-correction and Z-score testing methods were used to identify fetal autosomal aneuploidy for trisomy as described in Liao’s paper . The more advanced a tumor is, the more tumor DNA can be detected in the cfDNA. 2016;172(2):118–22. Placental tissues were also retained. a Ultrasound examination result at 30wk. Increasing amounts of evidence have shown that the circulating fetal DNA in maternal blood during pregnancy mainly originates from placental trophoblastic cells, although there are still small contributions from fetal tissues . Why do false positive results occur during NIPT? Each of us is carrying copy number variations, chunks of DNA which can be present in more or less copies compared to the general population. Canick JA, Palomaki GE, Kloza EM, et al. National Key Research and Development Program of China, 2016YFC1000700, 2016YFC1000703. Keep us updated!! This post is meant as a welcome and quick information / resources to those who have just found this sub. This has been demonstrated for NIPT. Saw a genetics counselor today and although she said that after inputting some numbers into her system and getting a result of 22% accuracy and 78% of it being a false positive she pushed and pushed for me to get a CVS today (as today would have been the last day to be able to get that as I turned 14 weeks). Ultrasound examination images. Firstly, I am sorry this is happening to you. Our hearts are broken and it all happens so fast, but we’re hopeful for recovery and a second chance for a healthy baby. If there is any suggestions for closure please do share . Further, the chimeric ratio varied from 32% to 72% at different sites, which suggested that there were significant regional variations in the T18 mosaicism in this placenta. Wishing you a safe delivery and all the good things! Yearb Pathol Lab Med. Lebo RV, Novak RW, Wolfe K, et al. doi: 10.1016/s1701-2163(15)31025-2. NIPT provided at 15GA gave a low risk result. The data of fetal ultrasound and cytogenetic results were collected. It is a more accurate screening test for Down syndrome and trisomy 18 than SIPS / IPS / Quad and it is done through a blood test. THIS IS A SCREENING AND NOT A DIAGNOSTIC TEST. Congratulations!!!!!!! BMJ. 2011;342(jan11 1):c7401. Chiu RWK, Akolekar R, Zheng YWL, et al. Your email address will not be published. 2013;33(6):598–601. These results confirmed that the fetus displayed T18 mosaicism, which indicated a false negative result for NIPT at 15GA. There are some options filled in, but you can also write in your own result. PubMed The prevelance of each of these disorders is influenced by the woman's age. I didn't make it to my second opinion appointment which would have been yesterday 2/10 , as I had my regular 4 week OB check last Monday 2/3 and there was no heartbeat. However, the appointment isn't until February 10th and I'm just feeling as if i cant even appreciate this pregnancy. 2017;96(1):7–18. A prenatal case with discrepant findings between non-invasive prenatal testing and fetal genetic testings. J Obstet Gynaecol Can. Correspondence to Hu H, Liu H, Peng C, Deng T, Fu X, Chung C, Zhang E, Lu C, Zhang K, Liang Z, Yang Y. After the ‘options for termination’ talk from the obstetrician we opted for the amniocentesis to confirm. Conventional aneuploidy screening remains “most appropriate” choice for general population, Cell-free DNA screening tests in the general obstetrical population. Hi there, I saw you had also posted a response on my original thread. https://doi.org/10.1186/s13039-017-0341-5, DOI: https://doi.org/10.1186/s13039-017-0341-5. I appreciate those who chime in as we all remember how difficult to be in this situation. Gao Y, Stejskal D, Jiang F, et al. People HAVE to know this and most OBs do not. Indeed, we've written about it extensively on this blog. Given the prevalence of each of these conditions, these data aren't all that surprising but they are still rather alarming. It feels so unreal!!! I should mention i already have an 8 year old son. This CPM is observed in around 1% of invasive tests. All authors have materially participated in the study and manuscript preparation. 2013;33(2):198–200. Pooled sensitivity for T13 sensitivity was closer to 0.900. PLoS One. Noninvasive prenatal testing: the future is now. 0153400300) . I’m 35 years old and 13w3d at the time of the scan. A cord blood sample and six placental biopsies (three from the maternal side and three from the fetal side) were taken for analysis. Did i not talk to the baby enough and let him know he was going to be OK? Current status in non-invasive prenatal detection of down syndrome, Trisomy 18, and Trisomy 13 using cell-free DNA in maternal plasma. Non-invasive prenatal testing (NIPT) which was established as an additional pregnancy test for detecting of the common fetal trisomies 21 (T21), 18 (T18) and 13 (T13), is rapidly becoming a common clinical practice . October-November was a busy month with lots of congresses relevant to our field. Bissell MG. Noninvasive prenatal diagnosis of fetal chromosomal Aneuploidies by maternal plasma nucleic acid analysis. Should DNA-based tests for Down syndrome screening replace biochemical tests? The amnio was done at 16 weeks and we were told we would get microarray and karyotype results in 10-14 days. This study was performed with the approval of Medical Ethics Committee of Guangdong Women and Children Hospital, and written informed consent was obtained from the patient. Occasionally this variation interferes with the NIPT tests. Current estimates indicate the twinning frequency in the US to be about one every 30 pregnancies. My fiance, luckily, was in the room and was able to catch more of what the doc said than I could have. For example, even in high-risk populations with the relatively high prevalences of trisomy 21 (1:185), 18 (1:470) and 13 (1:1500), a NIPT test with 99.9% specificity (false-positive rate of 0.1%) would yield PPVs of 90% for trisomy 21, 67% for trisomy 18, and 53% for trisomy 13 . It is very important to stress that the PPV of any test is not intrinsic to the test. My OB tried and tried to listen for the heartbeat with the doppler and we thought maybe the baby was hiding or play hard to find, so we opted for the sonogram and unfortunately that's when he told us there was no longer a heartbeat. Placental mosaicism means that the cffDNA from cytotrophoblast cells has a different karyotype than that of the true fetal DNA . You will see this come up in posts across this sub.
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