Nephropathic cystinosis (1–3) deserves a special place in the annals of clinical medicine as the first treatable lysosomal storage disease. The pathophysiology
itself, based upon the formation of cystine crystals within the lysosomes of cells, is remarkable. The presence of cystine
crystals provides a clue to the basic defect in cystinosis, i.e., failure to transport of cystine out of lysosomes (4–6).