Vogel I, Petersen OB, Christensen R, Hyett J, Lou S, Vestergaard EM. Chromosomal microarray as primary diagnostic genomic tool for pregnancies at increased risk within a population-based combined first-trimester screening program.
Ultrasound Obstet Gynecol 2018;
51:480-486. [PMID:
28608362 DOI:
10.1002/uog.17548]
[Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 05/24/2017] [Accepted: 06/02/2017] [Indexed: 06/07/2023]
Abstract
OBJECTIVE
To evaluate the performance of high-resolution chromosomal microarray (CMA) as the standard diagnostic approach for genomic imbalances in pregnancies with increased risk based on combined first-trimester screening (cFTS).
METHODS
This was a retrospective study of genomic findings in a cohort of 575 consecutive pregnancies undergoing invasive testing because of a cFTS risk ≥ 1:300 on a publicly funded population-based screening program in the Central and Northern Regions of Denmark, between September 2015 and September 2016. Women with fetal nuchal translucency thickness ≥ 3.5 mm or opting for non-invasive prenatal testing (NIPT) were excluded. Comparative genomic hybridization was performed using a 180-K oligonucleotide array on DNA extracted directly from chorionic villus/amniocentesis samples. Genomic outcomes were reported in relation to cFTS findings.
RESULTS
Of the 575 pregnancies that underwent invasive testing, CMA detected 22 (3.8% (95% CI, 2.5-5.7%)) cases of trisomies 21, 18 and 13, 14 (2.4% (95% CI, 1.4-4.0%)) cases of other types of aneuploidy and 15 (2.6% (95% CI, 1.5-4.3%)) cases with a pathogenic or probably pathogenic copy number variant (CNV). Of the 15 CNVs, three were > 10 Mb and would probably have been detected by chromosomal analysis, but the other 12 would most probably not have been detected using conventional cytogenetic techniques; therefore, the overall detection rate of CMA (8.9% (95% CI, 6.8-11.5%)) was significantly higher than that estimated for conventional cytogenetic analysis (6.8% (95% CI, 5.0-9.1%)) (P = 0.0049). Reducing the cFTS risk threshold for invasive diagnostic testing to 1 in 100 or 1 in 50 would have led, respectively, to 60% or 100% of the pathogenic CNVs being missed.
CONCLUSIONS
CMA is a valuable diagnostic technique that can identify an increased number of genomic aberrations in pregnancies at increased risk on cFTS. Limiting diagnostic testing to pregnancies with a risk above 1 in 100 or 1 in 50, as proposed in contingent NIPT/invasive testing models, would lead to a significant proportion of pathogenic CNVs being missed at first-trimester screening. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.
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