[Genetic analysis of two fetuses with congenital heart defects and 3q microdeletion]

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.

Genomic DNA was extracted from fetal umbilical cord tissue, and chromosome copy number variations were detected by low coverage whole genome sequencing.

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.

3q29 microdeletion may result in CHD in combination with cleft lip and palate. Genomic CNVs can be detected by low coverage whole genome sequencing.