Glomerular lesions in patients with late-onset cystinosis with massive proteinuria.
3 siblings--2 brothers aged 18 and 13 years, and 1 sister, aged 11 years--with adolescent or late-onset cystinosis presented with massive proteinuria. At the time their glomerular filtration rate was normal or only modestly diminished. Though glomerular injury was evident, renal tubular functional abnormalities were also present. Renal biopsy revealed histopathologic features typical of the nephropathic form of cystinosis with the Fanconi syndrome: polykaryocytosis, varying degrees of glomerular sclerosis, thickening and reduplication of basement membrane, fused foot processes, dilated tubules with altered epithelial cell features, and interstitial fibrosis. Fine granular deposits of C3 and IgM are irregularly distributed in the glomeruli, findings which have not been described in cystinosis. These deposits are possibly immune complexes being deposited in the glomeruli unrelated to the cystine-storage disease or they may represent a localized activation of the complement system induced by the glomerular injury of cystinosis.
D000293:Adolescent; D001707:Biopsy, Needle; D002648:Child; D003176:Complement C3 / Q000032:analysis; D003554:Cystinosis / Q000150:complications / Q000235:genetics / Q000473:pathology*; D005198:Fanconi Syndrome / Q000150:complications / Q000473:pathology; D005260:Female; D005455:Fluorescent Antibody Technique; D005919:Glomerular Filtration Rate; D006801:Humans; D007075:Immunoglobulin M / Q000032:analysis; D007678:Kidney Glomerulus / Q000276:immunology / Q000473:pathology* / Q000648:ultrastructure; D008297:Male; D008854:Microscopy, Electron; D011507:Proteinuria / Q000150:complications / Q000473:pathology*; D013997:Time Factors
D003176:Complement C3; D007075:Immunoglobulin M