Prenatal Diagnosis of Chromosome 22q11.2 Deletions: Experiences in a Single Institution

Purpose: This study was designed to determine the frequency and echocardiographic findings of 22q11.2 deletions in fetuses with cardiac defects on fetal ultrasound or familial backgrounds of 22q11.2 deletions. Materials and methods: We retrospectively reviewed the medical and ultrasonographic records of 170 fetuses that underwent fluorescence in situ hybridization (FISH) analysis for chromosome 22q11.2 deletions between February 2001 and April 2013. Results: Among 145 fetuses with cardiac defects, six (4.1%) had 22q11.2 deletions. Deletions of 22q11.2 were detected in 6 (5%) of the 120 fetuses with conotruncal defects: 5 (8.9%) of 56 with tetralogy of Fallot (TOF) and 1 (5.9%) of 17 with double outlet right ventricle (DORV). No deletions were found in cases of pulmonary atresia, truncus arteriosus, right aortic arch, or transposition of the great arteries. No 22q11.2 deletions were found in non-conotruncal cardiac malformations. Among 25 fetuses with familial backgrounds of 22q11.2 deletions, one (4%) had a maternally inherited 22q11.2 deletion with no cardiac findings. Conclusion: Knowledge of the frequency and echocardiographic findings of 22q11.2 deletions might be helpful for prenatal genetic counseling. It is advisable to perform FISH analysis for 22q11.2 deletions in pregnancies exhibiting conotruncal cardiac defects such as TOF or DORV.