How does cell-based NIPT perform against chorionic villous sampling and cell-free NIPT in detecting trisomies and copy number variations? A clinical study from Denmark.

OBJECTIVES: We aimed to compare cell-based NIPT (cbNIPT) to chorionic villus sampling (CVS), and to examine the test characteristics of cbNIPT in the first clinical validation study of cbNIPT compared to cell-free NIPT (cfNIPT).

MATERIAL AND METHODS: Study 1: Women (N=92) who accepted CVS were recruited for cbNIPT (53 normal and 39 abnormal). Samples were analyzed with chromosomal microarray (CMA).Study 2: Women (N=282) who accepted cfNIPT were recruited for cbNIPT. cfNIPT was analyzed using sequencing and cbNIPT by CMA.

RESULTS: Study 1: cbNIPT detected all aberrations (32/32) found in CVS; trisomies 13, 18 and 21 (23/23), pathogenic copy number variations (CNVs) (6/6) and sex chromosome aberrations (3/3). cbNIPT detected 3/8 cases of mosaicism in the placenta.Study 2: cbNIPT detected all trisomies found with cfNIPT (6/6) and had no false positive (0/246). One of the three CNVs called by cbNIPT was confirmed by CVS but was undetected by cfNIPT, two were false positives. cbNIPT detected mosaicism in five samples of which two were not detected by cfNIPT. cbNIPT failed in 7.8% compared to 2.8% in cfNIPT.

CONCLUSION: Circulating trophoblasts in the maternal circulation provides the potential of screening for aneuploidies and pathogenic CNVs covering the entire fetal genome. This article is protected by copyright. All rights reserved.