Cystinuria

Abstract

Metabolic stone disease is the leading etiology in children with urolithiasis. Ten percent of these cases are caused by cystinuria. In the last decades the genetic origin of cystinuria was clearly defined with two major gene defects in the SALC3A1 gene on chromosome 2 and in the SLC7A9 gene on chromosome 19. As a consequence the reabsorption of dibasic amino acid cystine in the proximal renal tubules is disturbed. Renal colics caused by urolithiasis in the adolescent patient represent the classical clinical picture. Diagnosis is made by quantitative determination of amino acids in 24 h urine sampling with elevated excretion of the cystine. Treatment includes dilution and alkalinization of urine in mild cases and pharmacotherapy with D-penicillinamine and Alpha-mercaptopropionylglycine in severe cases. In the future, new approaches such as the antisense technology will open a new therapeutic gate.

Keywords

Urolithiasis - cystinuria - genetic disorder - children