Relationship Between Gene-Phenotype and Clinical Manifestations of Chromosomal Copy Number Variations Indicated by Non-Invasive Prenatal Testing

Abstract

Objective: To analyze the clinical value of non-invasive prenatal testing (NIPT) in detecting chromosomal copy number variations (CNVs) and to explore the relationship between gene expression and clinical manifestations of chromosomal copy number variations. Methods: 3551 naturally conceived singleton pregnant women who underwent NIPT were included in this study. The NIPT revealed abnormalities other than sex chromosome abnormalities and trisomy 13, 18, and 21. Pregnant women with chromosome copy number variations underwent genetic counseling and prenatal ultrasound examination. Interventional prenatal diagnosis and chromosome microarray analysis (CMA) were performed. The clinical phenotypes and pregnancy outcomes of different prenatal diagnoses were analyzed. Additionally, a followup was conducted by telephone to track fetal development after birth, at six months, and one year post-birth. Results: A total of 53 cases among 3551 cases showed chromosomal copy number variation. Interventional prenatal diagnosis was performed in 36 cases: 27 cases were negative and 8 were consistent with the NIPT test results. This indicates that NIPT’s positive predictive value (PPV) in CNVs is 22.22%. Conclusion: NIPT has certain clinical significance in screening chromosome copy number variations and is expected to become a routine screening for chromosomal microdeletions and microduplications. However, further interventional prenatal diagnosis is still needed to identify fetal CNVs.