Combined diagnosis of QF-PCR and CNV-Seq in fetal chromosomal abnormalities: A new perspective on prenatal diagnosis.

Objective: This study aimed to evaluate the effect of QF-PCR and CNV-seq in diagnosing prenatal fetal chromosomal aberrations, explore the advantages and necessity of multimethod joint diagnosis.

Methods: We chose pregnant women with the indication of fetal chromosome examination in our hospital last year, collected 657 cases of amniotic fluid for QF-PCR and CNV-seq analyzes.

Results: While detecting aneuploidy, the coincidence rate of QF-PCR and CNV-seq was 100% (56/56). For all 46 chromosomes, 523 cases (79.60%, 523/657) coincided precisely, 128 cases (19.48%, 128/657) showed abnormality with CNV-seq, 8 cases (1.22%, 8/657) revealed abnormality by QF-PCR. In serological Down's syndrome screening, 328 cases showed a high risk of trisomy 21, of which CNV-seq and QF-PCR were consistent in 4 cases (1.22%, 4/328), CNV-seq found 87 cases of CNVs in 78 samples except for chromosomal aneuploidy abnormalities, among these, 18 cases (20.69%, 18/87) were polymorphic, 7 cases (8.05%, 7/87) might cause disease, 13 cases (14.94%, 13/87) caused disease explicitly, 21 cases (24.14%, 21/87) were possibly benign, 17 cases (19.54%, 17/87) were explicitly benign, and the classification of 11 cases (12.64%, 11/87) was unclear.

Conclusion: QF-PCR and CNV-seq were highly consistent in diagnosing chromosomal aneuploidy. The high risk of serological Down's screening might not only due to the aneuploidy of chromosomes 21, 18, and NTD, but also the microdeletion or microduplication of all 46 chromosomes. So using CNV-seq combined with QF-PCR could effectively reduce the risk of missed diagnosis.