Objective: To simultaneously detect fetal aneuploidies and single gene diseases using a novel noninvasive prenatal testing (NIPT) method called the Targeted And Genome-wide simultaneous sequencing (TAGs-seq). Design: Comparison of TAGs-seq NIPT results with conventional NIPT and diagnostic results. Setting: Shenzhen People’s Hospital and Chinese PLA General Hospital Population or Sample: 26 normal pregnancies, 7 pregnancies with fetal aneuploidies, 7 pregnancies with fetal achondroplasia (ACH) or thanatophoric dysplasia (TD), 18 pregnancies with ACH/TD-like ultrasound findings, and 10 pregnancies with fetal risk of beta-thalassemia. Methods: Plasma cfDNA was amplified by TAGs-seq to simultaneously obtain the whole-genome sequence of 0.1-3× depth and reads on target genes of >1000× depth. The whole-genome sequence was analyzed for fetal aneuploidy risk using a binary hypothesis T-score, and the reads on target genes were analyzed for single gene diseases by calculating minor allelic frequency of loci on FGFR3 and HBB. Main Outcome Measures: Concordance between the TAGs-seq NIPT, conventional NIPT and diagnostic results. Results: Consistent to conventional NIPT and diagnostic results, all cases of fetal aneuploidies and fetal ACH/TD were correctly identified from 58 pregnancies by TAGs-seq NIPT with high sensitivities and specificities. Two cases of paternal mutations of beta-thalassemia were correctly identified by TAGs-seq NIPT from 10 pregnancies, although one false-negative result was obtained. Conclusions: The TAGs-seq assay demonstrated a good potential to simultaneously detect fetal aneuploidies and single gene diseases as a novel NIPT method.
Objectives: To determine the temporal persistence of residual cell-free DNA (cfDNA) of deceased co-twin in maternal circulation after selective fetal reduction and evaluate its long-lasting effect on noninvasive prenatal testing (NIPT) results. Design: Prospective observational study Setting: The Third Affiliated Hospital of Guangzhou Medical University Population: Dichorionic diamniotic twins (n=5) underwent selective fetal reduction of a co-twin with trisomy. Methods: With consent, maternal blood was collected immediately before reduction and periodically after reduction until birth. CfDNA of each maternal blood sample was sequenced for NIPT and analyzed for fetal trisomies and fetal fractions. Main Outcome Measured: Detectable T-scores for trisomy identification and three types of fetal fractions including the total fetal fraction, the fetal fraction of the deceased co-twin, and the fetal fraction of the surviving co-twin.