Clinical variability of chromosome 22q11.2 deletion syndrome.

22q11.2 deletion syndrome (22q11.2 DS) is a disorder that has multiple symptoms and affects various organs and systems. Despite the great variability of clinical manifestations, common 22q11.2 DS includes congenital heart defect, immunodeficiency, characteristic facial features, palatal defects, developmental and/or learning disabilities, and hypocalcaemia. We present the cases of three patients with 22q11.2 DS that we have observed. Heart defects were revealed in all cases, and tetralogy of Fallot in one of them. Immune system disorders in these cases were highly variable and did not correlate with aplasia or hypoplasia of the thymus. Cleft palate was diagnosed only in one case. Characteristic facial features were presented in all cases but they were not significant and varied from subtle to mild. Developmental disability was presented by motor delays in two cases. Hypocalcaemia was revealed in one patient, and seizures were absent. Only one case completely fit CATCH-22 syndrome (cardiac defects, abnormal facies, thymic hypoplasia, cleft palate, and hypocalcaemia caused by22q11.2 deletion). The other cases had three out of the five main features, with some other, less significant signs also presented. In some cases, even just a few signs should be the reason for further examination to exclude 22q11.2 deletion syndrome. Currently, immunological disorders are not a significant determinant in the diagnosis of this syndrome, and timely correction of heart defects can reduce the number of recurrent respiratory infections. A multidisciplinary approach to the management of these patients and providing timely, complex medical care will prevent serious complications.