Background: A ventricular septal defect (VSD) is the most common form of congenital heart disease and is one of the most common cardiovascular anomalies in individuals with chromosome 22q11 deletion syndrome. However, the frequency of a chromosome 22q11 deletion in patients with a VSD is not known. In addition, among patients with a VSD, it is not clear whether particular types of VSD or associated cardiovascular phenotypic features are associated with a chromosome 22q11 deletion.
Methods: We prospectively enrolled 125 patients with a conoventricular (n = 100), posterior malalignment (n = 14), or conoseptal hypoplasia (n = 11) VSD who were admitted to Children's Hospital of Philadelphia between November 1991 and December 2001. Patients were studied for a chromosome 22q11 deletion by using fluorescence in situ hybridization.
Results: A chromosome 22q11 deletion was detected in 12 (10%) of the 125 patients. Anatomic features that were significantly associated with a chromosome 22q11 deletion included abnormal aortic arch sidedness, an abnormal aortic arch branching pattern, a cervical aortic arch, and discontinuous pulmonary arteries. There was no correlation between the type of VSD and chromosome 22q11 deletion. Of 20 patients with an abnormal aortic arch and/or discontinuous pulmonary arteries, 45% had a chromosome 22q11 deletion compared with only 3% of those with a left aortic arch, normal aortic arch branching pattern, and continuous branch pulmonary arteries
Conclusions: A chromosome 22q11 deletion is common in individuals with a conoventricular, posterior malalignment, or conoseptal hypoplasia VSD and anomalies of the aortic arch or branch pulmonary arteries. On the basis of these findings, at a minimum, we recommend testing for a chromosome 22q11 deletion in patients with these types of VSD who have abnormalities of aortic arch sidedness or branching, a cervical aortic arch, and/or discontinuous pulmonary arteries. Testing of patients with these types of VSD but a normal aortic arch and pulmonary arteries may be performed routinely or guided by the presence of associated noncardiovascular features of chromosome 22q11 deletion syndrome.