NIH conference. Cystinosis: progress in a prototypic disease

Area of Science:

• Biochemistry
• Genetics
• Pediatrics

Background:

• Nephropathic cystinosis is a rare, inherited lysosomal storage disease characterized by the accumulation of cystine within lysosomes.
• The primary defect involves impaired lysosomal cystine efflux, leading to cellular damage and multisystemic manifestations, including renal failure and Fanconi syndrome.

Purpose of the Study:

• To review the comprehensive aspects of nephropathic cystinosis, encompassing its history, underlying defect, pathogenesis, clinical features, diagnostic approaches, and therapeutic strategies.
• To evaluate the efficacy of oral cysteamine therapy in managing nephropathic cystinosis in children before and after renal transplantation.

Main Methods:

• A review incorporating lysosomal membrane transport studies and clinical reports.
• A historically controlled 7-year trial of oral cysteamine therapy in 148 children (0-12 years) with nephropathic cystinosis before renal transplant.
• Evaluation of 34 post-transplant patients (9-29 years) receiving oral cysteamine and symptomatic treatment for late complications.

Main Results:

• Oral cysteamine significantly reduced leukocyte cystine levels by over 80%.
• In pre-transplant patients, cysteamine improved growth and preserved renal function compared to controls.
• Topical cysteamine eyedrops effectively cleared corneal cystine crystals in young children.

Conclusions:

• Cystinosis is a treatable lysosomal storage disorder with oral cysteamine offering significant benefits.
• Early intervention with oral cysteamine in children can improve growth and delay or prevent renal deterioration.
• Long-term oral cysteamine therapy may help prevent non-renal complications following renal transplantation.