Ultraschall Med 2020; 41(02): 175-185
DOI: 10.1055/a-0651-0459
Original Article
© Georg Thieme Verlag KG Stuttgart · New York

Follow-Up Studies of cf-DNA Testing from 101 Consecutive Fetuses and Related Ultrasound Findings

Ultraschallbefunde und follow-up-Untersuchungen nach 101 auffälligen nicht-invasiven Pränataltests (NIPT)
Seher Basaran
1   Medical Genetics, Istanbul Medical Faculty, Istanbul, Turkey
,
Recep Has
2   Women Health Centre, MEDIZON, Istanbul, Turkey
,
Ibrahim Halil Kalelioglu
3   Obstetrics and Gynecology, Istanbul Medical Faculty, Istanbul, Turkey
,
Birsen Karaman
1   Medical Genetics, Istanbul Medical Faculty, Istanbul, Turkey
,
Melike Kirgiz
4   Genetic Diagnosis Center, PREMED, Istanbul, Turkey
,
Tahir Dehgan
4   Genetic Diagnosis Center, PREMED, Istanbul, Turkey
,
Bilge Nihan Satkin
4   Genetic Diagnosis Center, PREMED, Istanbul, Turkey
,
Tugba Sarac Sivrikoz
3   Obstetrics and Gynecology, Istanbul Medical Faculty, Istanbul, Turkey
,
Atil Yuksel
2   Women Health Centre, MEDIZON, Istanbul, Turkey
› Author Affiliations
Further Information

Publication History

22 November 2016

26 June 2018

Publication Date:
25 September 2018 (online)

Abstract

Purpose To determine the true- and false-positive rates of cf-DNA testing in a cohort of patients from tertiary care centers and assess the impact of ultrasound examinations in pregnancy management.

Materials and Methods Clinical, cytogenetic and ultrasound data of 101 consecutive fetuses were collected retrospectively. Cases were classified into five groups according to the ultrasound findings. Karyotyping, interphase FISH and microarray techniques were used for follow-up studies.

Results The overall false-positive rate was low for trisomy 21 (T21, 8.2 %), but significantly higher for trisomy 18 (T18, 40 %), monosomy X (MX, 50 %), X/Y trisomies (57.1 %), trisomy 13 (T13, 71.4 %). While single cases of trisomy 16, trisomy 22 and 8q duplication positive in cf-DNA were confirmed, 3 microdeletions (1p36 and two 22q11.2) were not. About 75 % of confirmed T21’s and all confirmed T18 and T13 had major markers and/or malformations. While false-negative cases (two T21, one T18 and one T13) were identified due to abnormal ultrasound findings, all false-positive cases were normal sonographically. Ultrasound findings of confirmed trisomy 16, 22, dup8q, monosomy X and other X/Y aneuploidies were unspecific. Term placenta studies were helpful to assess the role of confined mosaicism in unconfirmed cf-DNA test results. A vanishing twin has been observed as the likely cause of one false-positive T18.

Conclusion Our study contributes clinical data on discrepant cf-DNA testing results, corroborates the need for confirmational invasive testing and underscores the benefit of expert ultrasound in the prevention of fatal diagnostic errors.

Zusammenfassung

Zweck Ermittlung der Korrekt- und Falsch-Positiv-Rate von NIPT bei Patienten eines Zentrums der Tertiärversorgung sowie des Nutzens von Ultraschalluntersuchungen im Schwangerschaftsmanagement.

Material und Methoden Klinische, zytogenetische und Ultraschalldaten von 101 konsekutiven Schwangerschaften wurden retrospektiv ausgewertet. Abhängig vom Ultraschallbefund wurden diese in fünf Gruppen unterteilt. Für Nachfolgestudien wurden Karyotypisierung, Interphasen-FISH und Microarray-Techniken verwendet.

Ergebnisse Die Falsch-Positiv-Rate für Trisomie 21 war niedrig (T21, 8,2 %), jedoch deutlich höher für Trisomie 18 (T18, 40 %), Monosomie X (MX, 50 %), XXY, XXX, XYY (57,1 %) und Trisomie 13 (T13, 71,4 %). Während Einzelfälle für Trisomie 16, Trisomie 22 und 8q Duplikation bestätigt werden konnten, war dies für 3 Mikrodeletionen (1p36 und zwei 22q11.2) nicht der Fall. Etwa 75 % der bestätigten T21 und alle bestätigten T18 und T13 hatte auffällige Ultraschallbefunde. Alle falsch-negativen Fälle (zwei T21, ein T18 und ein T13) wurden aufgrund von auffälligen Ultraschallbefunden identifiziert, dagegen waren alle falsch-positiven Fälle sonografisch unauffällig. Die Ultraschallbefunde bei bestätigter Trisomie 16, Trisomie 22, Dup8q, Monosomie X und andere X/Y-Aneuploidien waren unspezifisch. Nachfolgende Plazentauntersuchungen waren hilfreich, um die Rolle von plazentalen Mosaiken in den Fällen mit falsch-positiver Testung zu beurteilen. Ein vanished twin war die wahrscheinliche Ursache eines falsch-positiven Trisomie18-Befundes im NIPT.

Schlussfolgerung Unsere Studie liefert weitere klinische Daten zu nicht bestätigten cf-DNA-Testergebnissen, bekräftigt die Notwendigkeit eines invasiven Tests zur Bestätigung und unterstreicht die Bedeutung von spezialisierten Ultraschalluntersuchungen zur Vermeidung von fatalen diagnostischen Fehlern.

 
  • References

  • 1 Gil M, Akolekar R, Quezada M. et al. Analysis of cell-free DNA in maternal blood in screening for aneuploidies: meta-analysis. Fetal Diagn Ther 2014; 35: 156-173
  • 2 Taylor-Phillips S, Freeman K, Geppert J. et al. Accuracy of non-invasive prenatal testing using cell-free DNA for detection of Down, Edwards and Patau syndromes: a systematic review and meta-analysis. BMJ open 2016; 6: e010002
  • 3 Bianchi DW, Parker RL, Wentworth J. et al. DNA sequencing versus standard prenatal aneuploidy screening. N Engl J Med 2014; 370: 799-808
  • 4 Palomaki GE, Kloza EM, Lambert-Messerlian GM. et al. DNA sequencing of maternal plasma to detect Down syndrome: an international clinical validation study. Genet Med 2011; 13: 913-920
  • 5 Wax JR, Chard R, Cartin A. et al. Noninvasive prenatal testing: the importance of pretest trisomy risk and posttest predictive values. Am J Obstet Gynecol 2015; 212: 548-549
  • 6 Gao Y, Stejskal D, Jiang F. et al. False-negative trisomy 18 non-invasive prenatal test result due to 48, XXX,+ 18 placental mosaicism. Ultrasound Obstet Gynecol 2014; 43: 477-478
  • 7 Wang Y, Zhu J, Chen Y. et al. Two cases of placental T21 mosaicism: challenging the detection limits of non-invasive prenatal testing. Prenat Diagn 2013; 33: 1207-1210
  • 8 Smith M, Lewis KM, Holmes A. et al. A case of false negative NIPT for Down syndrome-lessons learned. Case Reports in Genetics 2014; 2014: 1-3 Article ID 823504
  • 9 Srebniak M, Diderich K, Noomen P. et al. Abnormal non-invasive prenatal test results concordant with karyotype of cytotrophoblast but not reflecting abnormal fetal karyotype. Ultrasound Obstet Gynecol 2014; 44: 109-111
  • 10 Dugo N, Padula F, Mobili L. et al. Six consecutive false positive cases from cell-free fetal DNA testing in a single referring centre. Journal of Prenatal Medicine 2013; 8: 31-35
  • 11 Wang JC, Sahoo T, Schonberg S. et al. Discordant noninvasive prenatal testing and cytogenetic results: a study of 109 consecutive cases. Genet Med 2014; 17: 234-236
  • 12 Wang Y, Chen Y, Tian F. et al. Maternal mosaicism is a significant contributor to discordant sex chromosomal aneuploidies associated with noninvasive prenatal testing. Clin Chem 2014; 60: 251-259
  • 13 Mardy A, Wapner RJ. Confined placental mosaicism and its impact on confirmation of NIPT results. American Journal of Medical Genetics Part C: Seminars in Medical Genetics 2016; 172: 118-122
  • 14 American College of Obstetricians and Gynecologists. Noninvasive prenatal testing for fetal aneuploidy. Committee Opinion No. 545. Obstet Gynecol 2012; 120: 1532-1534
  • 15 Gregg AR, Gross SJ, Best RG. et al. ACMG statement on noninvasive prenatal screening for fetal aneuploidy. Genet Med 2013; 15: 395-398
  • 16 Salomon L, Alfirevic Z, Audibert F. et al. ISUOG consensus statement on the impact of non-invasive prenatal testing (NIPT) on prenatal ultrasound practice. Ultrasound Obstet Gynecol 2014; 44: 122-123
  • 17 Dondorp W, de Wert G, Bombard Y. et al. Non-invasive prenatal testing for aneuploidy and beyond: challenges of responsible innovation in prenatal screening. Eur J Hum Genet 2015; 23: 1438-1450
  • 18 Brady P, Brison N, Van Den Bogaert K. et al. Clinical implementation of NIPT – technical and biological challenges. Clin Genet 2016; 89: 523-530
  • 19 Grace MR, Hardisty E, Dotters-Katz SK. et al. Cell-Free DNA Screening: Complexities and Challenges of Clinical Implementation. Obstet Gynecol Surv 2016; 71: 477-487
  • 20 Zhang H, Gao Y, Jiang F. et al. Non-invasive prenatal testing for trisomies 21, 18 and 13: clinical experience from 146 958 pregnancies. Ultrasound Obstet Gynecol 2015; 45: 530-538
  • 21 Hochstenbach R, Nikkels PG, Elferink MG. et al. Cell-free fetal DNA in the maternal circulation originates from the cytotrophoblast: proof from an unique case. Clinical case reports 2015; 3: 489-491
  • 22 Lebo RV, Novak RW, Wolfe K. et al. Discordant circulating fetal DNA and subsequent cytogenetics reveal false negative, placental mosaic, and fetal mosaic cfDNA genotypes. J Transl Med 2015; 13: 260 , 16 pages
  • 23 Grati FR, Malvestiti F, Ferreira JCPB. et al. Fetoplacental mosaicism: potential implications for false-positive and false-negative noninvasive prenatal screening results. Genet Med 2014; 16: 620-624
  • 24 Osborne CM, Hardisty E, Devers P. et al. Discordant noninvasive prenatal testing results in a patient subsequently diagnosed with metastatic disease. Prenat Diagn 2013; 33: 609-611
  • 25 Mao J, Wang T, Wang BJ. et al. Confined placental origin of the circulating cell free fetal DNA revealed by a discordant non-invasive prenatal test result in a trisomy 18 pregnancy. Clin Chim Acta 2014; 433: 190-193
  • 26 Pan Q, Sun B, Huang X. et al. A prenatal case with discrepant findings between non-invasive prenatal testing and fetal genetic testings. Mol Cytogenet 2014; 7: 48
  • 27 Bayindir B, Dehaspe L, Brison N. et al. Noninvasive prenatal testing using a novel analysis pipeline to screen for all autosomal fetal aneuploidies improves pregnancy management. Eur J Hum Genet 2015; 23: 1286-1293
  • 28 Choi H, Lau T, Jiang F. et al. Fetal aneuploidy screening by maternal plasma DNA sequencing: “false positive” due to confined placental mosaicism. Prenat Diagn 2013; 33: 198-200
  • 29 Wapner RJ, Babiarz JE, Levy B. et al. Expanding the scope of noninvasive prenatal testing: detection of fetal microdeletion syndromes. Am J Obstet Gynecol 2015; 212: 332. e1–9
  • 30 Gross SJ, Stosic M, McDonald-McGinn DM. et al. Clinical experience with single-nucleotide polymorphism-based non-invasive prenatal screening for 22q11. 2 deletion syndrome. Ultrasound Obstet Gynecol 2016; 47: 177-183