Renal histopathology of the nail-patella syndrome in a two-year-old boy.

A two-year-old child with the clinical stigmata of nail-patella syndrome, congenital urinary tract anomalies and proteinuria underwent renal biopsy. Electron microscopy revealed characteristic electron lucent areas and collagen fibril-like deposits in the glomerular basement membrane. Of special interest, electron dense deposits were seen in subendothelial areas of the capillary loops and immunofluorescent staining was striking, particularly for IgM, in a peripheral capillary loop pattern.