“…We have recently found eighty times as much free-cystine in cystinotic as compared The basic defect in metabolism leading to the formawith normal leukocytes [23]. This fact, coupled with tion of cystine crystals in the rare inherited disease, the normal plasma concentration of cystine found in cystinosis, is not known [2,27,30]. The cystine is these children [4], suggested a defect in the transport thought to cause both the renal tubular defects of the of cyst(e)ine (cystine and/or cysteine) in cystinotic Fanconi syndrome which appear during the first year of cells, analogous to the apparent defect in cystine translife, and the progressive renal glomerular damage which port in cells of the renal tubules in the otherwise unleads to death of affected children [12,20].…”