cystinosis

Cystinosis is a lysosomal storage disease characterized by the abnormal accumulation of free cystine, the oxidized dimer of the amino acid cysteine in lysosomes, eventually leading to intracellular crystal formation throughout the body, e.g. in kidneys.

It is genetically inheritable in the autosomal recessive fashion via CTNS (AR) gene. It characterized by systemic accumulation of the amino acid cystine within lysosomes, proximal tubulopathy and by progressive chronic kidney disease. If untreated, it leads to progressive cellular dysfunction and multiorgan involvement. The disease most commonly presents in infancy with renal Fanconi syndrome and, without treatment, progresses to end-stage kidney disease (ESKD) in childhood. Extra-renal manifestations affecting the eyes, thyroid, muscle, pancreas, and central nervous system may develop later in life. Early diagnosis and lifelong cystine-depleting therapy improve growth, delay progression to ESKD, and reduce many systemic complications. Nevertheless, despite treatment, the mean age at death for individuals born between 1985 and 1999 has been 29 years.