CTNS mutations in patients with cystinosis

Cystinosis is an autosomal recessive lysosomal storage disease caused by mu tations in the gene CTNS, The CTNS gene product, cystinosin, has 367 amino acids and seven transmembrane domains and is thought to transport cystine o ut of lysosomes. The most common form of cystinosis, the nephropathic or in fantile type, is characterized by renal failure at 10 years of age and othe r systemic complications. To date, 32 different CTNS mutations have been de scribed in nephropathic cystinosis patients. Intermediate cystinosis, with later onset of renal disease, has been associated with three different CTNS mutations. Benign or nonnephropathic cystinosis, with symptoms related onl y to corneal crystals and photophobia, has been associated with two other C TNS mutations. In general, only certain splicing or missense mutations are associated with milder cystinosis phenotypes. Hum Mutat 14:454-458, 1999. P ublished 1999 Wiley-Liss, Inc.dagger.