Congenital heart defects and chromosomal anomalies including 22q11 microdeletion (CATCH 22).

OBJECTIVE: To analyze the frequency of chromosomal anomalies or 22q11 microdeletion in patients with congenital heart defects and other congenital anomalies; to describe the clinical phenotype of children with the 22q11 microdeletion and with chromosomal anomalies; to evaluate patients' clinical evolution; and to provide genetic counseling for families.

METHODS: The study included 46 patients with congenital heart defects and other anomalies and patients with a phenotype consistent with 22q11 microdeletion observed between 1999 and 2001. Confirmation of the heart defect was accomplished through echocardiography, magnetic resonance angiography or cardiac catheterization. Karyotyping with high resolution banding and detection of 22q11 microdeletion with FISH techniques were performed. We excluded patients with trisomy 21, 13 and 18, 45,X and deletion of 7q11.23. Patients with 22q11 microdeletion underwent immunology studies and evaluation of parathyroid function. Clinical evolution was evaluated. Chromosome and FISH studies were performed on parents of affected children (25 couples).

RESULTS: Forty-six children were included, of whom twelve (26.1%) had chromosomal anomalies (group A), fourteen (30.4%) had 22q11 microdeletion (group B) and the remaining twenty (43.5%) had normal karyotype and negative FISH studies (group C). In group A septal heart defects predominated. This group had significant morbidity, with surgical correction in three patients, early development of pulmonary hypertension, failure to thrive and serious neurological problems. Two patients died. In group B conotruncal heart defects (7/14) and ventricular septal defects (5/14, two associated with cervical aortic arch) predominated. The most significant morbidity was related to cardiac pathology, with surgical correction in seven cases (50%). Immune function defects and parathyroid function problems were mild, requiring no therapeutic measures. One patient died.

CONCLUSION: In the presence of heart defects associated with other congenital anomalies, karyotyping is mandatory and if clinical features are compatible, 22q11 microdeletion should be specifically sought with FISH techniques. Detection of chromosomal anomalies has a significant impact on prognosis and follow-up of patients, as well as on genetic counseling of families.