CYSTINOSIS

Nephropathic cystinosis is an autosomal recessive inborn error of meta bolism characterized by the lysosomal storage of the disulphide amino acid cystine. It produces a variety of clinical manifestations includi ng failure to thrive, the renal Fanconi syndrome, eye findings, and en d-stage renal disease. A variety of phenotypes are known; however, the molecular defect underlying any of the forms has not yet been identif ied. Therapy of cystinosis with cysteamine averts the otherwise inevit able renal failure, but systemic therapy does not improve the corneal keratopathy. A number of presentations in this review detail approache s to gene identification, systemic therapy with cysteamine, measuremen t of cystine, and pathophysiological effects at the cellular and clini cal level.