Cystinosis is a rare genetic disorder that leads to the accumulation of the amino acid cystine within cells, causing crystal formations that damage various organs and tissues. This condition primarily affects the kidneys and eyes but can also impact the brain, muscles, liver, thyroid, pancreas, and testes. Early diagnosis and treatment are necessary to manage the disease effectively, for as long as possible. Learn more about cystinosis types, symptoms, and treatment options.*

Types of Cystinosis

Nephropathic Cystinosis

Nephropathic cystinosis, also known as infantile or early-onset cystinosis, is the most common and severe form, affecting about 95% of individuals with the condition. 

Symptoms typically appear within the first 18 months of life and include renal Fanconi syndrome, where nutrients are improperly absorbed, leading to:

• Growth delays, 
• Rickets, and 
• Other complications.

If untreated, children with nephropathic cystinosis will experience kidney failure by age 10 and will require a kidney transplant.

Intermediate Cystinosis

Intermediate cystinosis, or adolescent/juvenile cystinosis, manifests later in childhood or adolescence with symptoms similar to the nephropathic form but generally less severe. 

This type progresses more slowly, but without treatment patients usually face kidney failure in their teens or twenties, necessitating a transplant.

Non-Nephropathic Cystinosis

Non-nephropathic, or ocular cystinosis, primarily affects the eyes, causing light sensitivity due to cystine crystals in the corneas. 

Unlike the other forms, this type does not typically lead to kidney damage or other systemic symptoms. 

Diagnosis often occurs in middle-aged adults due to the absence of early symptoms.

Symptoms and Diagnosis

Cystinosis symptoms vary based on the type and onset age. Nephropathic cystinosis symptoms, appearing between the ages of six and 18 months, include:

• Excessive thirst, 
• Frequent urination, 
• Vomiting,  
• Dehydration, and 
• Growth delays. 

Intermediate cystinosis shares these symptoms but appears later and less severely while non-nephropathic cystinosis presents primarily with photophobia.

Diagnosis involves:

• Blood tests to measure cystine levels in white blood cells, 
• Genetic testing to identify mutations in the CTNS gene, 
• Urinalysis to check for nutrient loss, and 
• Eye exams to detect corneal crystals. 

For those with a family history, prenatal testing can identify the condition before birth.

Treatment and Prognosis

The primary treatment for cystinosis is cysteamine, a cystine-depleting agent that, when administered early, can delay kidney damage and improve growth. 

Cysteamine is available as:

• Cystagon™, requiring doses every six hours, or 
• Procysbi™, a delayed-release form taken every 12 hours. 

For corneal crystals, the FDA-approved cysteamine eye drops Cystaran™ and Cystadrops™ are used.

Despite treatment, most patients with nephropathic or intermediate cystinosis will eventually require a kidney transplant. 

Dialysis may be used temporarily, but transplants offer better long-term outcomes. 

Though cystine does not accumulate in transplanted kidneys, it can still affect other organs, necessitating lifelong medication.

Life expectancy for individuals with cystinosis has improved significantly, with many living well into adulthood, and some surpassing 50 years of age. 

Early and consistent treatment is key to managing symptoms and delaying the progression of the disease.

*Cleveland Clinic. (n.d.) Cystinosis. Retrieved from https://my.clevelandclinic.org/health/diseases/24657-cystinosis 

Responsum Health closely vets all sources to ensure that we always provide you with high-quality, reliable information. We do not, however, endorse or recommend any specific providers, treatments, or products, and the use of a given source does not imply an endorsement of any provider, treatment, medication, or procedure discussed within.