Renal disease in adolescents with type I diabetes mellitus: a report of the Southwest Pediatric Nephrology Study Group.

Although 30% to 40% of patients with type I diabetes mellitus develop diabetic nephropathy, the usual signs of clinical nephropathy are often thought to be delayed until adulthood. We studied 13 adolescents with type I diabetes mellitus for 5 to 14 years who had renal biopsies completed because of clinical problems, including proteinuria, hematuria, or hematuria plus proteinuria. Changes typical of diabetes were seen by light and immunofluorescence microscopy; evidence of other renal diseases was not noted. On electron microscopy evaluation, glomerular basement membrane width was increased in 11 patients. In seven patients, mesangial volume was elevated above the normal range. Peripheral capillary filtration surface density was diminished below the normal range in five patients. Thus, several of these adolescents had severe glomerular lesions that were indicative of overt diabetic nephropathy. Within 2 to 3 years after biopsy, at least two patients were dialysis dependent. Thus, the adolescent diabetic patient with a relatively short duration of diabetes may be developing progressive diabetic renal lesions, and the clinical signs and symptoms at presentation may not be those typically seen in diabetic nephropathy.