Cystinuria: clinical practice recommendation

Cystinuria (OMIM 220100) is an autosomal recessive hereditary disorder in which high urinary cystine excretion leads to formation of cystine stones due to its low solubility at normal urinary pH. We developed clinical practice recommendation for diagnosis, surgical and medical treatment, and follow up of cystinuria patients. Elaboration of these Clinical Practice Recommendations spanned from June 2018 until December 2019 with a consensus conference in January 2019. Selected topic areas were chosen by the co-chairs of the conference. Working groups focusing on specific topics were formed. Group members performed systematic literature review using Medline, drafted the statements, and discussed them. They included geneticists, medical biochemists, paediatric and adult nephrologists, paediatric and adult urologists experts in cystinuria, Metabolic Nephropathy Joint Working Group of the European Reference Network for Rare Kidney Diseases (ERKNet) and eUROGEN members. Overall 20 statements were produced to provide guidance on diagnosis, genetic analysis, imaging techniques, surgical treatment (indication and modalities), conservative treatment (hydration, dietetic, alkalinisation, cystine binding drugs), follow up, self-monitoring, complications (renal failure and hypertension), and impact on quality of life. Due to the rarity of the disease and the poor level of evidence in the literature, these statements could not be graded. This clinical practice recommendation provides guidance on all aspects of the management of both adults and children with cystinuria, including diagnosis, surgery and medical treatment.

Keywords: D-penicillamine; cystine; cystinuria; potassium citrate; tiopronin and urolithiasis.