Type I diabetes mellitus in a patient with chromosome 22q11.2 deletion syndrome

We describe a patient with type I diabetes, clinical findings consistent wi th velocardio-facial syndrome, and a chromosome 22q11.2 deletion. A nine-ye ar-old boy presented with a history of polyuria, polydipsia, weight loss, h yperglycemia, ketosis, serum insulin antibodies, and a low C-peptide level. He had distinctive facial features, learning disabilities, short stature, and a history of glottic web and clubfoot. Although a normal karyotype was obtained, fluorescence in situ hybridization (FISH) revealed a submicroscop ic deletion in the DiGeorge/velocardiofacial syndrome critical region at 22 q11.2. His maternal half-brother also carried a chromosome 22q11.2 deletion . His mother has similar facial features and hypoparathyroidism. Autoimmune problems associated with chromosome 22q11.2 deletions have been reported. We suggest that the defects in immune regulation due to T-cell deficiency i n chromosome 22q11.2 deletion syndrome may predispose to autoimmune disorde rs, including type I diabetes mellitus, (C) 2001 Wiley-Liss, Inc.