Pathophysiology and Treatment of Cystinuria

Abstract

Cystinuria is a relatively rare autosomal recessive disorder that manifests early in life and is associated with the development of kidney stones composed of cystine. It is due to mutations in two genes that are involved in the transport of cystine, neutral, and dibasic amino acids in the proximal tubule of the kidney. Patients are at risk for developing chronic kidney disease. Diagnosis is typically established with stone analysis and quantitative urinary cystine excretion. These patients may form extremely large stones requiring percutaneous nephrolithotomy. Stone-prevention strategies include dietary modifications (increased fluid intake and limitation of sodium and animal protein consumption), urine pH manipulation, and thiol-binding agents. These patients should be followed closely, and preemptive stone removal with ureteroscopy should be considered to limit the necessity for more invasive procedures. This review contains 2 figures and 38 references. Key Words: a-mercaptopropionyl glycine, amino acid transport, chronic kidney disease, cystinuria, SLC3A1, SLC7A9, thiol-binding agent, urinary pH manipulation