The 22q11.2 microdeletion is found in most of DiGeorge and velocardiofacial syndromes. These individuals have a wide range of anomalies including congenital heart disease, palatal abnormalities, characteristic facial features, hypocalcaemia, immune deficiency, and learning difficulties. Congenital heart disease, particularly conotruncal malformations are associated with 29% of deletions. This syndrome may be inherited as an autosomal dominant trait, but the majority of patients (93%) have a de novo deletion. To access the presence of the microdeletion in those individuals whose phenotipic changes suggested abnormalities in chromosome 22, a study has been made in several children with congenital heart defects.