Nephropathic Cystinosis

What is nephropathic cystinosis?

Nephropathic cystinosis is a rare disease caused by a buildup of the amino acid cystine, typically bringing kidney problems. This disease sees its onset during infancy. 

What are the symptoms of nephropathic cystinosis?

Symptoms typically appear between the first six and twelve months of life. The first signs are frequent urination, failure to thrive, feeding intolerance, and dehydration. The thyroid gland is often affected as well. 

Fanconi syndrome, meaning the kidneys cannot absorb the nutrients and minerals it needs to, is another common symptom. This will usually lead to severe kidney problems later in life, such as kidney disease or even kidney failure. These problems typically arise from ages ten to twelve. 

Other symptoms include: 

• Muscle wasting
• Weak bones
• Difficulty swallowing
• Diabetes
• Issues with attention, memory, coordination, and movement

What causes nephropathic cystinosis?

A mutated CTNS gene is responsible for nephropathic cystinosis. It is inherited in an autosomal recessive pattern. The mutation results in malfunctioning cystinosin proteins, which are responsible for transporting the amino acid cystine to lysosomes. When this protein does not do its job, there is an accumulation of cystine. 

How is nephropathic cystinosis diagnosed?

A physical exam is the first step in obtaining a diagnosis, including an eye exam. Family and patient history will be evaluated as well. Kidney function will be tested, and blood and urine tests will be used as well. 

What are the treatments for nephropathic cystinosis?

Treatment is symptomatic. Dialysis and kidney transplants can treat the severe kidney problems, and medications can help to lower the amount of cystine in the body. 

Where can I find out more about nephropathic cystinosis?

• • National Kidney Foundation
  • NIH
  • NORD