Prenatal diagnosis of 22q11.2 deletion when ultrasound examination reveals a heart defect

The incidence of 22q11.2 deletion syndrome is approximately 1 in 5,000 births, and accounts for 5-30% of all heart defects, making it one of the more common genetic conditions in the population.

We employed fluorescence in situ hybridization (FISH) to study the incidence of 22q11.2 deletions in fetuses with cardiac anomalies detected on ultrasound examination.

Of 64 cases, 18 had visible chromosome anomalies. FISH testing for 22q11.2 deletion was performed on the remaining 46 cases, and five exhibited a 22q11.2 deletion. Three of the five had de novo deletions, one was maternally inherited, and one family declined testing.

FISH analysis for 22q11.2 deletion should be performed on all fetuses with cardiac defects (excluding hypoplastic left heart and echogenic focus) and a normal G-banded karyotype.