In
alkaptonuric ochronosis, the absence of
homogentisic acid oxidase results in the accumulation of
homogentisic acid in the body. Associated
renal failure is rare and usually occurs in the later stages of the disease. We report a 19-yr-old girl who presented initially with severe
renal failure, without family or past history of illness. There was no significant
proteinuria or
hematuria. No clinical evidence of pigmentation such as skin and subcutaneous cartilages was noted. However, pigment deposits were identified in the renal biopsy specimens obtained within a week after admission and another after a month. Two months later the
peritoneal dialysis fluid and skin progressively darkened, suggesting
ochronosis. This was confirmed by the detection of
homogentisic acid in the serum and urine. The patient expired in
renal failure. Renal biopsy tissues showed diffuse chronic tubulo-interstitial disease characterized by widespread tubular
atrophy, interstitial
fibrosis, and a moderate degree of
inflammation. Many tubular cells contained brown, coarsely granular ochronotic pigment (OP) and a few pigment casts were in the lumina. Similar deposits were also in the interstitium and within histiocytes. Ultrastructural studies of the glomeruli revealed small sparse OP deposits in the visceral and parietal epithelial cells, mesangial cells, and rare extracellular and basement membrane deposits. The tubulointerstitial changes were varied:
atrophy and dilatation of tubules, varying degrees of lysosomal OP and degeneration of tubular cells, casts containing OP with crystalline material, histiocytes distended with OP, and free interstitial pigment deposition.(ABSTRACT TRUNCATED AT 250 WORDS)