Disease background

Disease background

Types of cystinosis

There are three clinically recognised forms of cystinosis, depending on the age of presentation and degree of renal disease severity:1,2

Infantile nephropathic cystinosis

The most severe and frequent form, accounting for 95% of patients1,2

The major identifiable cause of renal Fanconi syndrome in children1,2

If untreated, leads to end-stage renal disease in the first decade of life1,2

Juvenile, or late-onset, nephropathic cystinosis

Accounts for 5% of patients1,2

Usually diagnosed later in childhood or during adolescence2

Symptoms are often more unspecific and incomplete compared with the infantile form, e.g. nephrotic syndrome or mild proximal tubulopathy2

Slower progression to end-stage renal disease1

Adult, or ocular, cystinosis

Rarely diagnosed before adulthood1,2

Characterised by photophobia due to corneal cystine accumulation1,2

Kidneys may still be affected1,2


Nephropathic cystinosis occurs as a result of mutations in the gene CTNS, which codes for the lysosomal cystine-proton cotransporter cystinosin. To date, more than 160 pathogenic variants have been identified in the CTNS gene.1-3

Cystinosin is ubiquitously expressed on lysosomal membranes; when the protein is functional, cystine efflux from the lysosome is driven by a proton gradient. However, in the absence of a functional transporter, cystine accumulates and crystallises inside the lysosome.1,4

Normal lysosome
Normal lysosome
Lysosome in nephropathic cystinosis
Lysosome in nephropathic cystinosis

Cystine crystals have a number of pathological effects, such as:1,2

Activation of monocytes and macrophages, which leads to the production of pro-inflammatory substances
Enhanced apoptosis
Increased oxidative stress

More recent research has also demonstrated that cystinosin plays a broader role in intracellular vesicle trafficking, cell signalling, lysosomal dynamics and exocytosis, all of which may be disrupted by cystinosin dysfunction.5

To date, the exact mechanisms behind the clinical symptoms of the disease are not fully understood and may differ between tissues.2,5


Explore the sections below to find out more


Disease background

Types of cystinosis and pathophysiology of nephropathic cystinosis


Identifying symptoms

Clinical characteristics of cystinosis through different life stages

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Diagnosing cystinosis

Investigations required to support a diagnosis of cystinosis

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General management

Recommendations for management and monitoring of cystinosis patients

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Clinical recommendations

Explore the cystinosis Clinical Decision Support Programme (CDSP)

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HCP tools and resources

Useful tools and resources for you and your patients

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