The clinical utility of microarray technologies applied to prenatal cytogenetics in the presence of a normal conventional karyotype: a review of the literature

ABSTRACT The clinical utility of microarray technologies when used in the context of prenatal diagnosis lies in the technology's ability to detect submicroscopic copy number changes that are associated with clinically significant outcomes. We have carried out a systematic review of the literature to calculate the utility of prenatal microarrays in the presence of a normal conventional karyotype. Amongst 12 362 cases in studies that recruited cases from all prenatal ascertainment groups, 295/12 362 (2.4%) overall were reported to have copy number changes with associated clinical significance (pCNC), 201/3090 (6.5%) when ascertained with an abnormal ultrasound, 50/5108 (1.0%) when ascertained because of increased maternal age and 44/4164 (1.1%) for all other ascertainment groups (e.g. parental anxiety and abnormal serum screening result). When additional prenatal microarray studies are included in which ascertainment was restricted to fetuses with abnormal ultrasound scans, 262/3730 (7.0%) were reported to have pCNCs. © 2013 The Authors. Prenatal Diagnosis published by John Wiley & Sons Ltd. What's already known about this topic? Microarray testing gives an increase in detection rate of unbalanced structural abnormalities in both the postnatal and prenatal contexts. What does this study add? This work attempts to calculate the overall detection rate, and the detection rates for different ascertainment categories, of clinically significant prenatal copy number changes detected by microarrays in the presence of a normal conventional karyotype by combining data obtained from several published studies.