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What Causes Cystinosis?

Cystinosis is an inherited disorder that is found in some families. Because of the way it is inherited, it is called a recessive genetic disease. When 2 parents with the gene have a child together, there is a 1 in 4 chance that the child will have cystinosis.1,2

Recessive Genetic Disease Recessive Gene

The cystinosis gene has a mutation that prevents cystine from being transported out of the lysosome.2 This can result in cystine buildup and crystal formation in the cells of various body organs.3

References: 1. Cystinosis Research Network Web site. Cystinosis symptoms & treatment. Available at: Accessed March 13, 2013. 2. Gahl WA, Kuehl EM, Iwata F, Lindblad A, Kaiser-Kupfer MI. Corneal crystals in nephropathic cystinosis: natural history and treatment with cysteamine eyedrops. Mol Genet Metab. 2000;71:100-120. 3. Cystinosis Research Foundation Web site. What is cystinosis. Available at: Accessed June 15, 2020.


CYSTARAN (CYSTEAMINE OPHTHALMIC SOLUTION) 0.44% STERILE is a cystine-depleting agent indicated for the treatment of corneal cystine crystal accumulation in patients with cystinosis.

Important Safety Information:

To minimize contaminating the dropper tip and solution, care should be taken not to touch the eyelids or surrounding areas with the dropper tip of the bottle. Keep bottle tightly closed when not in use.

There have been reports of benign intracranial hypertension (or pseudotumor cerebri) associated with oral cysteamine treatment that has resolved with the addition of diuretic therapy. There have also been reports associated with ophthalmic use of cysteamine; however, all of these patients were on concurrent oral cysteamine.

CYSTARAN contains benzalkonium chloride, which may be absorbed by soft contact lenses. Contact lenses should be removed prior to application of solution and may be reinserted 15 minutes following its administration.

CYSTARAN is for topical ophthalmic use only.

The most frequently reported ocular adverse reactions occurring in ≥ 10% of patients were sensitivity to light, redness, and eye pain/irritation, headache and visual field defects.