Cystinuria: An Overview of Diagnosis and Medical Management

Abstract

Cystinuria is a genetic disorder that causes recurrent nephrolithiasis. It is the most common type of monogenic stone disease accounting for 6%-8% of pediatric nephrolithiasis. Due to recurrent episodes of nephrolithiasis, it is associated with a very high prevalence of chronic kidney disease. Life-long medical treatment to reduce stone formation is critical in preventing chronic kidney disease and renal failure in cystinuria. In this article, we provide an overview of cystinuria with a special emphasis on medical treatment options including new agents such as alpha-lipoic acid.

Prenatal diagnosis of cystinuria with a heterozygous pathogenic variant in SLC7A9 gene associated with isolated hyperechogenic fetal kidneys: A case report

“…The prevalence of this pathology is 1/7000 and the average age of first kidney stone is 13. 33 The reason why urolithiasis begins postnatally in childhood is that the pH of fetal urine is +/− 7, preventing cystine stones formation. During childhood, the pH decreases, giving rise to the clinical manifestations of urolithiasis.…”

“…The assay cannot distinguish between cystine and cystine–thiol drug complex, making the measurement of cystine concentration inaccurate. However, it is recommended to prescribe 1 mg of tiopronin for every 1 mg of cystine excreted per 24 h. 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 In case of renal calculi, treatment is mainly symptomatic, with the use of analgesics. If treatment fails, ureteroscopy or extracorporeal shock wave lithotripsy may be considered.…”

“…The assay cannot distinguish between cystine and cystine–thiol drug complex, making the measurement of cystine concentration inaccurate. However, it is recommended to prescribe 1 mg of tiopronin for every 1 mg of cystine excreted per 24 h 3–37 . In case of renal calculi, treatment is mainly symptomatic, with the use of analgesics.…”

“…This tubulopathy is characterized by a defect in tubular reabsorption, leading to abundant urinary excretion of COLA‐type dibasic amino acids, such as cystine, ornithine, arginine, and especially lysine. The prevalence of this pathology is 1/7000 and the average age of first kidney stone is 13 33 . The reason why urolithiasis begins postnatally in childhood is that the pH of fetal urine is +/− 7, preventing cystine stones formation.…”