We are currently establishing a data-base of patients with cystinuria in the United Kingdom and examining the genetic defects responsible for the formation of stones in these patients. We will then identify if there is any genotype-phenotype association in respect to frequency of stone recurrence and response to treatment. Concurrently we are also isolating, and immortalising, proximal tubular cells from the urine of cystinuric patients to study the molecular biology of this condition.