What is Cystinosis?
Cystinosis is a rare metabolic disease that affects approximately 500 people in the United States (mostly children),and about 2,000 people worldwide. This disease causes the amino acid “cystine” to accumulate in the cells of the body. Over time, the cystine damages various organs including the kidneys, liver, muscles, white blood cells, eyes, and central nervous system. Other complications include muscle wasting, growth loss, difficulty swallowing, and developmental delays.
Termed an “orphan disease,” Cystinosis is a disorder which has not been “adopted” by the pharmaceutical industry because it provides little financial incentive for the private sector to make and market new medications to treat it or prevent it.
Symptoms of Cystinosis
There are three clinical forms of Cystinosis: Infantile (nephropathic) Cystinosis, late-onset Cystinosis, and benign Cystinosis. Infantile Cystinosis is the most severe and the most common type of Cystinosis. Children with Infantile Nephropathic Cystinosis generally appear normal at and during the first 9-10 months of life. By one year of age, symptoms occur including excessive thirst and urination, failure to thrive, growth retardation, metabolic acidosis and other chemical and renal tubular abnormalities. Children often appear pale and thin and have short stature. The abnormally high loss of phosphorous in the urine leads to rickets. After one year of age, cystine crystals appear in the cornea and cause a severe sensitivity to light (photophobia). Children with Cystinosis also have an increased level of cystine in their white blood cells. In time, patients can develop problems such as hypothyroidism, severe muscle weakness and central nervous system complications. These children have normal intelligence, but have an unusual defect in short-term visual memory. Many have poor GI motility. Cystagon TM causes hyper secretion of gastric acid, resulting in gastric distress.
Without specific treatment, children with Cystinosis progress to end-stage kidney failure by an average age of nine years. In the past, this meant death.Now these patients can receive kidney dialysis or transplantation. However, even with successful treatment, these children can go on to develop abnormalities in other organs and often experience muscle wasting, growth loss, difficulty swallowing, and developmental delays.
The only treatment for Cystinosis is cysteamine. It is the only drug that slows the progression of the disease by removing the cystine from the cells. In 1994, the new product CystagonTM was made available in capsule form however it has a very bad taste and must be taken every six hours, every day, without fail. Although this has led to a much better future for children and young adults with Cystinosis, Cystagon TM is very hard on their bodies and is not a cure.