Isabelle Monier1, Aline Receveur2, Véronique Houfflin-Debarge3, Valérie Goua4, Vanina Castaigne5, Jean-Marie Jouannic6, Eve Mousty7, Anne-Hélène Saliou8, Hanane Bouchghoul9, Thierry Rousseau10, Anne-Sylvie Valat11, Marion Groussolles12, Florent Fuchs13, Guillaume Benoist14, Sophie Degre15, Jérôme Massardier16, Vassilis Tsatsaris17, Pascale Kleinfinger18, Jennifer Zeitlin19, Alexandra Benachi20. 1. Obstetrical, Perinatal and Pediatric Epidemiology Research Team, Epidemiology and Statistics Research Center, Université de Paris, Institut national de la santé et de la recherche médicale, Institut national de la recherche agronomique, Paris, France; Department of Obstetrics and Gynaecology, Antoine Béclère Hospital, AP-HP, Paris Saclay University, Clamart, France. Electronic address: isabelle.monier@inserm.fr. 2. Department of Cytogenetics and Reproductive Biology, Antoine Béclère Hospital, AP-HP, Paris Saclay University, Clamart, France. 3. Department of Obstetrics and Gynaecology, Jeanne de Flandres University Hospital, Lille, France. 4. Department of Obstetrics and Gynaecology, Poitiers University Hospital, Poitiers, France. 5. Department of Obstetrics and Gynaecology, Centre Hospitalier Intercommunal de Créteil, Créteil, France. 6. Fetal Medicine Department, Armand-Trousseau Hospital, AP-HP, Sorbonne University, Paris, France. 7. Department of Gynaecology and Obstetrics, Nîmes University Hospital, Nîmes, France. 8. Department of Obstetrics and Gynaecology, Brest University Hospital, Brest, France. 9. Department of Obstetrics and Gynaecology, Bicêtre Hospital, AP-HP, Paris Saclay University, Le Kremlin Bicêtre, France. 10. Department of Obstetrics and Gynaecology, Dijon University Hospital, Dijon, France. 11. Department of Obstetrics and Gynaecology, Lens Hospital, Lens, France. 12. Department of Obstetrics and Gynecology, Paule de Viguier Hospital, Toulouse University Hospital, Toulouse, France. 13. Department of Obstetrics and Gynecology, Montpellier University Hospital Center, Montpellier, France. 14. Department of Obstetrics and Gynecology, Caen University Hospital Center, Caen, France. 15. Department of Obstetrics and Gynecology, Le Havre University Hospital Center, Le Havre, France. 16. Department of Obstetrics and Gynecology, Hospices Civils de Lyon, Bron, France. 17. Department of Obstetrics and Gynecology, Cochin Hospital, AP-HP, Paris-Descartes University, Paris, France. 18. Laboratoire CERBA, Saint-Ouen-l'Aumône, France. 19. Obstetrical, Perinatal and Pediatric Epidemiology Research Team, Epidemiology and Statistics Research Center, Université de Paris, Institut national de la santé et de la recherche médicale, Institut national de la recherche agronomique, Paris, France. 20. Department of Obstetrics and Gynaecology, Antoine Béclère Hospital, AP-HP, Paris Saclay University, Clamart, France.
Abstract
BACKGROUND: Compared with standard karyotype, chromosomal microarray analysis improves the detection of genetic anomalies and is thus recommended in many prenatal indications. However, evidence is still lacking on the clinical utility of chromosomal microarray analysis in cases of isolated fetal growth restriction. OBJECTIVE: This study aimed to estimate the proportion of copy number variants detected by chromosomal microarray analysis and the incremental yield of chromosomal microarray analysis compared with karyotype in the detection of genetic abnormalities in fetuses with isolated fetal growth restriction. STUDY DESIGN: This retrospective study included all singleton fetuses diagnosed with fetal growth restriction and no structural ultrasound anomalies and referred to 13 French fetal medicine centers over 1 year in 2016. Fetal growth restriction was defined as an estimated fetal weight of <tenth percentile for gestational age identified in ultrasound reports. For this analysis, we selected fetuses who underwent invasive genetic testing with karyotype and chromosomal microarray analysis results. Data were obtained from medical records and ultrasound databases and postmortem and placental examination reports in case of spontaneous stillbirths and terminations of pregnancy. Following the American College of Medical Genetics and Genomics guidelines, copy number variants were classified into 5 groups as following: pathogenic, likely pathogenic, variant of unknown significance, likely benign, and benign. RESULTS: Of 682 referred fetuses diagnosed with isolated fetal growth restriction, both karyotype and chromosomal microarray analysis were performed in 146 fetuses. Overall, the detection rate of genetic anomalies found by chromosomal microarray analysis was estimated to be 7.5% (11 of 146 [95% confidence interval, 3.3-11.8]), including 10 copy number variants classified as pathogenic and 1 copy number variant classified as likely pathogenic. Among the 139 fetuses with normal karyotype, 5 were detected with pathogenic and likely pathogenic copy number variants, resulting in an incremental yield of 3.6% (95% confidence interval, 0.5-6.6) in chromosomal microarray analysis compared with karyotype. All fetuses detected with pathogenic or likely pathogenic copy number variants resulted in terminations of pregnancy. In addition, 3 fetuses with normal karyotype were detected with a variant of unknown significance (2.1%). Among the 7 fetuses with abnormal karyotype, chromosomal microarray analysis did not detect trisomy 18 mosaicism in all fetuses. CONCLUSION: Our study found that compared with karyotype, chromosomal microarray analysis improves the detection of genetic anomalies in fetuses diagnosed with isolated fetal growth restriction. These results support the use of chromosomal microarray analysis in addition to karyotype for isolated fetal growth restriction.
BACKGROUND: Compared with standard karyotype, chromosomal microarray analysis improves the detection of genetic anomalies and is thus recommended in many prenatal indications. However, evidence is still lacking on the clinical utility of chromosomal microarray analysis in cases of isolated fetal growth restriction. OBJECTIVE: This study aimed to estimate the proportion of copy number variants detected by chromosomal microarray analysis and the incremental yield of chromosomal microarray analysis compared with karyotype in the detection of genetic abnormalities in fetuses with isolated fetal growth restriction. STUDY DESIGN: This retrospective study included all singleton fetuses diagnosed with fetal growth restriction and no structural ultrasound anomalies and referred to 13 French fetal medicine centers over 1 year in 2016. Fetal growth restriction was defined as an estimated fetal weight of <tenth percentile for gestational age identified in ultrasound reports. For this analysis, we selected fetuses who underwent invasive genetic testing with karyotype and chromosomal microarray analysis results. Data were obtained from medical records and ultrasound databases and postmortem and placental examination reports in case of spontaneous stillbirths and terminations of pregnancy. Following the American College of Medical Genetics and Genomics guidelines, copy number variants were classified into 5 groups as following: pathogenic, likely pathogenic, variant of unknown significance, likely benign, and benign. RESULTS: Of 682 referred fetuses diagnosed with isolated fetal growth restriction, both karyotype and chromosomal microarray analysis were performed in 146 fetuses. Overall, the detection rate of genetic anomalies found by chromosomal microarray analysis was estimated to be 7.5% (11 of 146 [95% confidence interval, 3.3-11.8]), including 10 copy number variants classified as pathogenic and 1 copy number variant classified as likely pathogenic. Among the 139 fetuses with normal karyotype, 5 were detected with pathogenic and likely pathogenic copy number variants, resulting in an incremental yield of 3.6% (95% confidence interval, 0.5-6.6) in chromosomal microarray analysis compared with karyotype. All fetuses detected with pathogenic or likely pathogenic copy number variants resulted in terminations of pregnancy. In addition, 3 fetuses with normal karyotype were detected with a variant of unknown significance (2.1%). Among the 7 fetuses with abnormal karyotype, chromosomal microarray analysis did not detect trisomy 18 mosaicism in all fetuses. CONCLUSION: Our study found that compared with karyotype, chromosomal microarray analysis improves the detection of genetic anomalies in fetuses diagnosed with isolated fetal growth restriction. These results support the use of chromosomal microarray analysis in addition to karyotype for isolated fetal growth restriction.