A familial syndrome of growth retardation, severe Fanconi-type renal disease and glomerular changes--a new entity?

Two young siblings had a syndrome of growth retardation, severe rickets, anemia, renal insufficiency, and renal tubular dysfunction, the last including acidosis, aminoaciduria, and polyuria. There was moderate psychomotor developmental delay. Neither child had cystinosis. Renal biopsy in the older child revealed severe glomerular abnormalities, with capillary wall thickening reminiscent of the hemolytic-uremic syndrome. The proximal convoluted tubules were lined with short, cuboidal cells containing mildly abnormal mitochondria. There was also thinning of brush border microvilli and basolateral infoldings, perhaps as the result of regressive changes, and interstitial fibrous tissue was moderately increased. The etiology of the tubular and glomerular changes is uncertain. We believe these patients represent a previously unreported hereditary syndrome sharing certain clinical features with severe nephropathic cystinosis.