Cistinuria

AUTORI

ABSTRACT

Cystinuria

Cystinuria is a rare inherited disorder, generally transmitted as an autosomal recessive trait. It is characterized by defective resorption (for deficits of transporter proteins) of cystine and dibasic amino acids at the level of renal proximal tubules and, to a lesser extent, of intestinal cells. The low solubility of cystine at physiologic urinary acidity leads to its precipitation in the form of crystals and stones, causing the urinary tract obstruction. The two genes responsible for cystinuria are SLC3A1 (chromosome 2p21) and SLC7A9 (chromosome 19q12), encoding for the heavy subunit rBAT and the light subunit b0,+AT of the renal b0,+ transporter, respectively. Cystinuria can be classified in type I and non-type I on the basis of urinary excretion rate of cystine. Alternatively, cystinuria can be classified as type A (SLC3A1 gene mutated), type B (SLC7A9 gene mutated) and type AB (mutations on both genes). Clinical symptoms and positivity of laboratory tests are the basis for diagnosis. Detection of mutations in SLC3A1 and SLC7A9 genes can be used to confirm the diagnosis and to identify possible carriers within the patient family. Although many advances have been made in the understanding of genetic and physiologic basis of cystinuria, the treatment still involves prevention of stone formation by dietary measures and drug therapy coupled with surgical intervention for stone removal.

BIBLIOGRAFIA