Nail-patella glomerulopathy without associated constitutional abnormalities.

A 17-year-old boy presented with a history of longstanding hematuria and non-nephrotic proteinuria without renal insufficiency, for which renal biopsy was performed. The findings by routine light microscopy and direct immunofluorescence study were mild and nonspecific. Electron microscopy, however, demonstrated the unexpected finding of distinct collagen fibrils within capillary wall basement membranes, typical of the nail-patella syndrome. Repeat physical examination following the biopsy confirmed the presence of normal nails and patellae, and radiographs of the knees were also normal. The boy's renal disease was stable at last follow-up. The authors briefly discuss the differential diagnosis, and suggest that this case represents an unusual manifestation of the nail-patella syndrome, in which the glomerular changes are present in the absence of the usual associated constitutional abnormalities.