title: Natural history of adolescent-onset cystinosis.
abstract: Cystinosis is a rare autosomal recessive disease caused by mutations of the CTNS gene in which cystine accumulates throughout the body as a result of a defective efflux of cystine from lysosomes. Three phenotypic forms have been described according to the age of onset and the severity of the clinical symptoms: infantile, intermediate, and ocular non-nephropathic cystinosis. Here we report the natural history of cystinosis in a 55-year-old man with intermediate nephropathic cystinosis diagnosed at 9 years of age. Although tubulopathy was unnoticed in the early years, he required transplantation at age 16. Sequencing analysis of all the CTNS exons revealed that the proband is homozygous for a 21-bp in-frame deletion in exon 5 (c. 198_218del21), resulting in an in-frame deletion of 7 amino acids from the N-terminal domain of the cystinosin protein. Our patient has had relatively mild extra-renal disease despite lack of early cysteamine therapy. He has been able to attend university and pursue a professional career into the 6th decade.
authors.affiliation: Department of Pediatrics, Alberta Children's Hospital, 2888 Shaganappi Trail, NW, Calgary, AB, T3B 6A8, Canada.
authors.forename: Julian P
authors.initials: JP
authors.lastname: Midgley
authors.forename: Reyhan
authors.initials: R
authors.lastname: El-Kares
authors.forename: François
authors.initials: F
authors.lastname: Mathieu
authors.forename: Paul
authors.initials: P
authors.lastname: Goodyer
mesh_terms: D000293:Adolescent; D017668:Age of Onset; D026921:Amino Acid Transport Systems, Neutral / Q000235:genetics*; D001483:Base Sequence; D002648:Child; D003543:Cysteamine / Q000627:therapeutic use; D003554:Cystinosis / Q000235:genetics* / Q000503:physiopathology* / Q000628:therapy; D005091:Exons; D017353:Gene Deletion; D006801:Humans; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D011837:Radiation-Protective Agents / Q000627:therapeutic use
chemical_list: D026921:Amino Acid Transport Systems, Neutral; C111445:CTNS protein, human; D011837:Radiation-Protective Agents; D003543:Cysteamine