# Noninvasive prenatal testing for the detection of fetal chromosome 17 microduplication: clinical implications and findings

## TL;DR

This paper shows that noninvasive prenatal testing can effectively detect chromosome 17 microduplications, improving fetal screening.

## Contribution

The study demonstrates the clinical utility of NIPT for detecting 17q12 microduplications, a less common application.

## Key findings

- NIPT detected four cases of 17q12 microduplications confirmed by CMA.
- The positive predictive value of NIPT for 17q12 microduplication was 75.0%.
- NIPT can reduce invasive testing while improving fetal CNV detection rates.

## Abstract

Noninvasive prenatal testing (NIPT) is widely used to screen for fetal aneuploidies. However, there are few reports of using NIPT for screening chromosomal microduplications and microdeletions. This study aimed to investigate the application efficiency of NIPT for detecting chromosomal microduplications.

Four cases of copy number gains on the long arm of chromosome 17 (17q12) were detected using NIPT and further confirmed using copy number variation (CNV) analysis based on chromosome microarray analysis (CMA).

The prenatal diagnosis CMA results of the three cases showed that the microduplications in 17q12 (ranging from 1.5 to 1.9 Mb) were consistent with the NIPT results. The karyotypic analysis excluded other possible unbalanced rearrangements. The positive predictive value of NIPT for detecting chromosomal 17q12 microduplication was 75.0%.

NIPT has a good screening effect on 17q12 syndrome through prenatal diagnosis, therefore it could be considered for screening fetal CNV during the second trimester. With the clinical application of NIPT, invasive prenatal diagnoses could be effectively reduced while also improving the detection rate of fetal CNV.