[Detection of cryptic copy number variations in a fetus with congenital heart disease by array-based comparative genomic hybridization].

ABSTRACT

OBJECTIVE: To detect the copy number variation (CNV) of a fetus with interrupted aortic arch and ventricular septal defect, in order to explore the underlying genetic causes of the congenital malformation, and investigate the feasibility of array-based comparative genomic hybridization (array-CGH) in molecular cytogenetic diagnosis. METHODS: The whole genome of the fetus with de novo apparently balanced translocations [46,XX,t(7;9)(q12;q21)] diagnosed by G-banding was scanned and analyzed by array-CGH, and the copy number variation was confirmed by fluorescence in situ hybridization (FISH). RESULTS: A pathologic submicroscopic CNV [del(22) (q11.2) (17 370 128-19 790 009, -2.42 Mb)] was identified and mapped by array-CGH. FISH test confirmed the microdeletion detected by array-CGH. CONCLUSION: The cryptic 22q11.2 deletion might be the reason leading to the congenital malformation of the fetus. This study provides evidence that apparently balanced translocations classified by conventional cytogenetic techniques may host additional submicroscopic CNVs which are not located at the breakpoints. Due to the high-resolution, high-throughput and high-accuracy, array-CGH is considered to be a powerful tool for submicroscopic CNVs detection.