Clinical characterization of 72 patients with del(22)(q11.2q11.2) from different ethnic backgrounds

Abstract

Background: DiGeorge syndrome (DGS), caused by a deletion del(22)(q11.2q11.2), is the most frequently observed microdeletion syndrome. There is a vast clinical heterogeneity in DGS, and several studies suggested also heterogeneity of clinical signs and phenotypic appearance to be related to ethnic differences. Here, clinical characteristics of 72 patients with molecular diagnosed deletion del(22)(q11.2q11.2) derived from different countries from Europe, America, Africa, and Asia are summarized and compared. Results: Unless ethnic differences, the expected major clinical signs were present in all cases. Frequent clinical manifestations found in this study were congenital heart disease with 68% (49/72), followed by dysmorphic features found in 61% (44/72); neurodevelopmental disorders were present in 43% (31/72) and thymus hypoplasia/aplasia in 32% (23/72). However, clinical features of the patients appeared/were recognized at different times during their lives. Within the group, under 2 years predominated heart disease, dysmorphic features, and hypocalcemia and/or hypoparathyroidism. In the group older than 2 years, the following combination of clinical findings was most frequent: dysmorphic features, congenital heart disease, intellectual disability, and immunological disorders. In the eight cases detected prenatally, abnormal sonographic findings were the major clinical signs (cardiovascular malformations and renal malformations). Conclusions: Despite the heterogeneous nature of the sample analyzed, a number of clinical findings could be highlighted to be useful for the clinical delineation of this DGS. Interestingly, diagnostic indicators may vary depending on the age at diagnosis. Finally, apparent differences in DGS patients from different regions seem to be rather due to applied test systems than to real differences in patients from different ethnicities.