Outcomes of pregnancies with trisomy 16 mosaicism detected by NIPT: a series of case reports.
Peng H, Yang J, Wang D, Guo F, Hou Y, Yin A. Mol Cytogenet. 2021;14(1):44. Published 2021 Sep 20. doi:10.1186/s13039-021-00559-w. Open Access: Learn more
Tags: Case Report / Case Series, 2021, China, RAAs
- “NIPT detected 12 cases of T16 and 2 cases of T16 mosaicism. Prenatal diagnosis confirmed 5 true positive cases and 9 false positive cases. Among the 5 true positive cases, 3 cases had ultrasound abnormalities. All of the 9 false positive cases continued their pregnancies. The newborns who were from these 9 false positive cases except 1 case (case 7) had low birth weights (< 2.5 kg) and there were also 2 premature deliveries.”
- “Conclusion: NIPT serves as a fast and early prenatal screening method, giving clues to chromosome abnormalities and providing guidance for managing pregnancy. Confined placental mosaicism in 16 pregnancies may be at higher risk for preterm delivery.”
Case Report: Paternal Uniparental Isodisomy and Heterodisomy of Chromosome 16 With a Normal Phenotype.
Zhang X, Liu L, Liu Y, Pan X. Front Pediatr. 2021;9:732645. Published 2021 Oct 22. doi:10.3389/fped.2021.732645. Open Access: Learn more
Tags: Case Report / Case Series, 2021, China, RAAs
- Case report of a pregnancy with an NIPT result positive for trisomy 16. CMA of amniocytes revealed paternal UPD 16.
Cell-free DNA test for pathogenic copy number variations: A retrospective study.
Duan HL, Li J, Wang WJ, et al. Taiwan J Obstet Gynecol. 2021;60(6):1066-1071. doi:10.1016/j.tjog.2021.09.018. Open Access: Learn more
Tags: Clinical Experience / Clinical Utility, 2021, Taiwan, CNVs
- Retrospective study of 29 pregnancies with prenatal diagnosis of fetal microdeletion/microduplication syndromes by CMA.
- 24 CNVs were identified by NIPT among the 21 fetuses with pathogenic CNVs, including 20 concordant CNVs and 21 discordant CNVs. Overall detection rate of NIPT for pathogenic CNVs >2 Mb was 69%.
- “Conclusion: Cell-free DNA test exhibited a moderate DR for pathogenic CNVs ＞2 Mb among fetuses with ultrasound abnormalities. Cell-free DNA test could provide an opportunity for early screening before the appearance of abnormalities on fetal ultrasound, while further clinical data and cost-effectiveness assessment are needed.”
Confined placental mosaicism of trisomy 6 detected through genome-wide NIPT was associated with placental abruption.
Nishiyama M, Wada S, Hasegawa F, et al. Clin Case Rep. 2021;9(12):e05155. Published 2021 Dec 5. doi:10.1002/ccr3.5155. Open Access: Learn more
Tags: Case Report, 2021, Japan, RAAs
- Case report of a pregnancy with a NIPT result positive for trisomy 6 and placental abruption.
Prenatal Identification of Confined Placental Mosaicism in Pregnant Women with Fetal Growth Restriction.
Miyagami K, Shirato N, Izumi M, et al. Reprod Sci. 2022;29(3):896-903. doi:10.1007/s43032-021-00772-3.
Tags: Clinical Experience / Clinical Utility, 2021, Japan, RAAs
- “cfDNA analyses of maternal plasma detected suspected CPM cases with chromosomal aneuploidy or copy number variations in 5 of 40 cases (12.5%). For 4 cases in which the entire placenta consisted of cells with chromosomal abnormalities, fetal growth was severely restricted. CPM can be screened by cfDNA analysis in maternal plasma, accounting for approximately 10% of the causes of moderate or severe FGR [fetal growth restriction], and the higher the proportion of abnormal karyotype cells in the placenta, the more severe the placental dysfunction and FGR.”
Expanding the application of non-invasive prenatal testing in the detection of foetal chromosomal copy number variations.
Wang C, Tang J, Tong K, et al. BMC Med Genomics. 2021;14(1):292. Published 2021 Dec 11. doi:10.1186/s12920-021-01131-6. Open Access: Learn more
Tags: Clinical Experience / Clinical Utility, 2021, China, RAAs, CNVs
- Study of 39,002 women who had NIPT. 473 pregnancies (1.213%) were screen positive for clinically significant fetal chromosome abnormalities by NIPT.
- PPVs for T21, T18, T13, SCA, RATs, and microdeletion/microduplication syndrome cases were 88.89%, 53.33%, 20.00%, 40.22%, 4.88%, and 49.02%, respectively.
- PPVs of CNVs of <5 Mb, 5–10 Mb, and >10 Mb were 54.55%, 38.46%, and 40.00%, respectively.
Genome-wide cell-free DNA screening: a focus on copy-number variants
Rafalko J, Soster E, Caldwell S, et al. Genet Med. 2021;23(10):1847-1853. doi:10.1038/s41436-021-01227-5. Open Access: Learn more
Tags: Laboratory Performance / Laboratory Experience, 2021, United States, CNVs
- In a cohort of 86,902 Expanded NIPT samples, this publication focuses on the 490 (0.56%) cases that were screen positive for at least 1 subchromosomal partial deletion/duplication. Diagnostic outcomes were available in 50% of these cases, in which the PPV was found to be greater than 70%.
Three years of clinical experience with a genome-wide cfDNA screening test for aneuploidies and copy-number variants
[published correction appears in Genet Med. 2021 May 6;:]. Soster E, Boomer T, Hicks S, et al. Genet Med. 2021;23(7):1349-1355. doi:10.1038/s41436-021-01135-8. Open Access: Learn more
Tags: Laboratory Performance / Laboratory Experience, Clinical Experience / Clinical Utility, 2021, United States, RAAs, CNVs
- This publication is a retrospective analysis of over 55,000 samples submitted for Expanded NIPT to the laboratory, with diagnostic outcomes available in over 40% of screen positive cases. The publication reports on testing indications, demographics, results, and performance. The authors noted that indications shifted during the 3-year period, with a decrease in referrals for ‘ultrasound findings’ (22.0% to 12.0%) and an increase in referrals of ‘no known high-risk indication’ (3.0% to 16.6%). Of the screen positive results, they reported that 25% would have been missed with NIPT limited to the common aneuploidies. They concluded that, although a broader patient population is using Expanded NIPT, the positivity rates and genome-wide events have remained stable at approximately 5% and 25%, respectively.
Outcome of publicly funded nationwide first-tier noninvasive prenatal screening
Van Den Bogaert K, Lannoo L, Brison N, et al. Genet Med. 2021;23(6):1137-1142. doi:10.1038/s41436-021-01101-4. Open Access: Learn more
Tags: Clinical Experience / Clinical Utility, 2021, Belgium, RAAs, CNVs
- Belgium was the first country to implement and fully reimburse NIPT as a first-tier screening for all pregnant women. In this publication, a consortium comprised of all the Belgian genetic center reports on the clinical experience during a 2-year period of offering Expanded NIPT as a first-tier testing option for all pregnant women. Of the 153,575 pregnancies screened, rare autosomal trisomies and partial deletions/duplications were found in 0.23% and 0.07% of cases, respectively. Invasive diagnostic obstetric procedures decreased by 52%. The authors conclude that their Expanded NIPT approach has been successfully implemented into prenatal care in Belgium and could possibly act as a framework for other countries offering NIPT.