Abstract: SA-PO0640
First Results of the European Cystinuria Registry
Session Information
- Monogenic Kidney Diseases: Tubular and Other
November 08, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Genetic Diseases of the Kidneys
- 1201 Genetic Diseases of the Kidneys: Monogenic Kidney Diseases
Authors
- Courbebaisse, Marie, Universite Paris Cite Faculte de Sante, Paris, France
- Weingarten, Ariel Martje, Center for Pediatrics and Adolescent Medicine, Heidelberg, Germany
- Capolongo, Giovanna, Department of Translation Medical Sciences, University of Campania "Luigi Vanvitelli", Naples, Italy
- Tostivint, Isabelle, service de Néphrologie, Hôpital La Pitié Salpétrière, Paris, France
- Decramer, Stéphane, service de Néphrologie Pédiatrique, Toulouse, France
- Lemoine, Sandrine, Service de néphrologie, dialyse et exploration fonctionnelle rénale, Hôpital Edouard Herriot, Hospices Civils de Lyon, Lyon, France
- Ferraro, Pietro Manuel, Department of Medicine Università degli Studi di Verona, Verona, Italy
- Lepore, Marta, Unit of Nephrology, Dialysis and Kidney Transplant Azienda Socio-Sanitaria territoriale (ASST) Papa Giovanni XXIII, Bergamo, Italy
- Türkkan, Özde Nisa, Marmara Universitesi, Istanbul, Turkey
- Olde Engberink, Rik Hg, Amsterdam UMC Locatie AMC, Amsterdam, NH, Netherlands
- Prot-Bertoye, Caroline, Universite Paris Cite Faculte de Sante, Paris, France
- Schaefer, Franz, Universitat Heidelberg Medizinische Fakultat Heidelberg, Heidelberg, BW, Germany
- Knebelmann, Bertrand, service de Néphrologie adultes, Hôpital Necker, Paris, France
- Servais, Aude, service de Néphrologie adultes, Hôpital Necker, Paris, France
Group or Team Name
- EUROCYS Consortium.
Background
Cystinuria is a rare autosomal recessive disorder in which high urinary cystine excretion leads to formation of cystine stones due to its low solubility at normal urinary pH (UpH). Our goal was to collect prospective data from children and adults with cystinuria followed in European centers.
Methods
EUROCYS is a multidisciplinary, multicenter registry of patients with cystinuria in which demographic, clinical, biological, radiological and therapeutic data are collected longitudinally and recorded via the European Rare Kidney Disease Registry platform.
Results
484 patients (306 adults, 178 children) have been included in 38 centers from 10 countries. Mean age at diagnosis and at inclusion were 17.8 (SD: 17.5) and 30.3 (21.0) yrs, respectively. Within the 12 months prior to visit, 13.8% had a urological surgery and 11.0% a spontaneous stone passage. Mean eGFR at inclusion was 87.8 ml/min/1.73m2 (24.5): 52.4%, 33.8%, 12.8%, 0.3%, and 0.8% of patients had CKD stages 1, 2, 3, 4 or 5, respectively. Mean UpH was 6.9 (0.8), below the recommended target of 7.5 to 8. Taking into account all visits with available UpH (n=213), only 25.3% of UpH were between 7.5 and 8, whereas 65.3% were below 7.5 and 9.4% above 8. UpH between 7 and 7.49 and below 7 were associated with an increased risk of new stones assessed by radiology during the following year, compared with UpH between 7.5 and 8 (OR 2.4, IC 1.0; 5.8, p=0.045 and 2.7, IC 1.2; 6.3, p=0.019, respectively). Mean 24-hour urinary volume was 2830 mL (874) in adults and 2560 mL/1.73m2 (1780) in children. Only 31.7% of adults and 46.7% of children had a urine volume above the recommended target of 3 L and 2 L/1.73m2, respectively. As alkalizing agent, 64.2% of patients received potassium citrate, 14.3% sodium bicarbonate and 6.1% potassium bicarbonate. As cystine binding drug, 18.5% received Tiopronin and 5.3% D-Penicillamine. The use of a cystine binding drug did not correlate with stone activity.
Conclusion
Despite alkalizing treatment, only one quarter of patients reach the recommended urinary pH level and less than half have an adequate urinary volume. Our data show for the first time that a urinary pH below 7.5 is associated with an increased risk of new stone.
Funding
- Commercial Support – Advicenne