Severe hyperglycemia after renal transplantation in a pediatric patient with a mutation of the hepatocyte nuclear factor-1beta gene.

After renal transplantation for congenital cystic kidney disease of unknown origin, a 14-year-old boy, who was previously normoglycemic, had "steroid-induced" diabetes mellitus, which was treated with insulin. Transplant failure from chronic rejection and subsequent transplant nephrectomy allowed discontinuation of corticosteroids, the gradual withdrawal of insulin and normoglycemia. The recent description of renal cysts and diabetes (RCAD) syndrome and a strong paternal family history of early-onset diabetes mellitus prompted genetic screening of the hepatocyte nuclear factor-1beta gene. A novel heterozygous frameshift mutation in exon 1 was identified, adding to the 12 kindreds thus far described. This case highlights the unmasking of the hyperglycemic component of the RCAD syndrome in the immediate postoperative period after renal transplantation and emphasizes the pleiotropic manifestations of this important genetic kidney disease.