Objective: To determine the nature of genomic copy number variations (CNVs) in two fetuses with congenital heart defects (CHD) and explore the correlation between 3q microdeletions and CHD.
Methods: Genomic DNA was extracted from fetal umbilical cord tissue, and chromosome copy number variations were detected by low coverage whole genome sequencing.
Results: Both fetuses had microdeletions of the long arm of chromosome 3. Fetus 1 had ventricular septal defect, cleft lip and palate, and a 1.66 Mb deletion on 3q29. The deleted region encompassed all of the critical genes for 3q29 microdeletion syndrome. Fetus 2 had overriding aorta, ventricular septal defect, and a novel 240 kb deletion on 3q28.
Conclusion: 3q29 microdeletion may result in CHD in combination with cleft lip and palate. Genomic CNVs can be detected by low coverage whole genome sequencing.