What would be missed in the first trimester if nuchal translucency measurement is replaced by cell free DNA foetal aneuploidy screening?

What would be missed in the first trimester if nuchal translucency measurement is replaced by cell free DNA foetal aneuploidy screening?
J Obstet Gynaecol. 2018 Feb 12;:1-4
Authors: Huang LY, Pan M, Han J, Zhen L, Yang X, Li DZ
Abstract
The aim of this study was to evaluate which chromosomal abnormalities in our cohort of foetuses with increased nuchal translucency (NT) in the first trimester of pregnancy could be detected by cell free (cf)DNA screening as well. There were 775 singleton pregnancies referred for cytogenetic testing due to an increased NT (≥3.0 mm). Chromosome aberrations were investigated using karyotyping or chromosomal microarray analysis (CMA). Karyotyping had been chosen for foetal cytogenetic testing by 446 patients, and CMA by 329 patients. Common aneuploidies (trisomies 21, 18, 13 and sex aneuploidies) were detected in 2.2% (99/446) and 1.8% (59/329) cases, respectively. In 329 with CMA testing, clinically significant copy number variations (CNVs) other than common aneuploidies were detected in 2.7% cases; among these, five had a pathogenic microscopic CNV, which could have been detected by karyotyping. There were four cases (1.2%) having a pathogenic submicroscopic CNV, which could have been missed by karyotyping. The total CMA detection rate (23.4%) was not statistically different from that (24.2%) by karyotyping (p > .05). The percentage of chromosomal aberrations, which cfDNA screening would miss...

Source: Journal of Obstetrics and Gynaecology - February 14, 2018 Category: OBGYN Tags: J Obstet Gynaecol Source Type: research