Use of Cysteamine in the Treatment of Cystinosis
Cystinosis is an inherited disease resulting in poor growth and kidney failure. There is no known cure for cystinosis, although kidney transplantation may help the renal failure and prolong survival. Both the kidney damage and growth failure are thought to be due to the accumulation of the amino acid cystine within the cells of the body. The cystine storage later damages other organs besides the kidneys, including the thyroid gland, pancreas, eyes, and muscle. The drug cysteamine (Cystagon; ProCysBi) is an oral medication given to patients with cystinosis prior to kidney transplantation. The drug works by reducing the level of cystine in the white blood cells and muscle tissue. The drug may also decrease levels of cystine in the kidneys and other tissues. This study has several goals: 1. Long-term surveillance of cysteamine treated patients. 2. Detection of new non-kidney complications of cystinosis. 3. Maintenance of a patient population for genetic testing (mutational analysis) of the cystinosis gene.\<TAB\>
• Diagnosis of cystinosis, whether classical or one of the variants with later onset or no renal complications.
• Patients will be diagnosed as having cystinosis based upon a leucocyte cystine content greater than 1 nmol half-cystine/mg protein (normal, less than 0.2) and a typical clinical course.