Cystinuria

Focus Group

David Goldfarb, MD. (Principal Investigator) | bio | New York University, New York, NY and Lenox Hill Hospital, New York, NY|

What's New?

Join the Cystinuria Registry

The International Cystinuria Registry is now operational. Participation of patients will help physicians and scientists learn more about this rare disease, and help design new treatments. To learn more about the Cystinuria registry at New York University, please send an e-mail to cystinuria@nyumc.org or visit the official registry site at New York University.

Biobank

The biobank started recruiting and we recently mailed the first consent forms to registry participants. If you are interested in joining, email us at www.cystinuria@nyumc.org and request a consent form. The biobank is open for all registry participants. We plan to collect blood, urine and stone samples (if available), for the biobank. Specimens will be stored at the Mayo Clinic in Rochester MN. Participants that are not seen in New York will receive a collection kit with instructions for the collection. There is no cost. International participants are welcome to join.

Clinical trials

Currently there are two clinical trials recruiting patients enrolled in the cystinuria registry. The first trial is to measure cystine capacity (Cyscap) in urine to predict stone recurrence.. The Cyscap test by Litholink Corporation, Chicago, IL, measures the cystine supersaturation (SS) or capacity of a patient's urine. The clinical course in cystinuria varies greatly from person to person. Some patients have mild disease with few stones in their lifetime while others are frequent stone formers necessitating multiple urologic procedures per year. We are trying to see if Cyscap predicts how people do clinically. This study is open to registry participants from the US.

The second clinical trial is to determine the effect of increasing dosages of cystine binding thiol drugs (CBTDs) on the amount of cystine in the urine of individuals with cystinuria. This study hopes to find the best way to dose CBTDs [either D-penicillamine (Cuprimine®) or tiopronin (Thiola®)] that should be given to cystinuria patients in order to allow the urine to take up more cystine and reduce the chance of kidney stones. Although CBTDs are normally given as per the "standard of care", there is no set guideline to determining the best dosage. Therefore, this may lead to dosages that are too small, resulting in kidney stones; or too large, resulting in unnecessary side effects. This study is open to registry participants seen at Lenox Hill Hospital.

For more detailed information about these trials, please email cystinuria@nyumc.org.

Quality of Life

The quality of life protocol will be operational soon. This study will be open to all participants enrolled in one of the RKSC registries.

The purpose of this study is to learn about Health-related Quality Of Life (HRQoL) in patients enrolled in the Rare Kidney Stone Consortium (RKSC) registries. All participants enrolled in the RKSC registries will be invited, via email or postal mail, to participate in this study.

Health-related quality of life in people with rare kidney stones included in the RKSC registries will be assessed. Instruments used in this protocol are the SF-10 for pediatric participants and SF-36v2 for adult participants. The administration of these surveys will be done online. Participants without a computer and/or internet access will participate using a paper version of these instruments. These surveys will be done at enrollment and annually thereafter.

Advocacy Organizations

International Cystinuria Foundation | www.cystinuria.org

Cystinuria Support Network | www.cystinuria.com

Internet Resources

NYU School of Medicine, Division of Nephrology - main site for the cystinuria registry

http://medicine.med.nyu.edu/nephrology/research/current/cystinuriaregistry

Cystinuria Support Network, active Yahoo email group

http://www.cystinuria.com and http://health.groups.yahoo.com/group/cystinuria-support-network/ and http://www.facebook.com/groups/2225138217/?fref=ts

International Cystinuria Foundation

http://www.cystinuria.org and http://www.facebook.com/groups/37121694952/

Rare Kidney Stone Consortium, main consortium web site

http://www.rarekidneystones.org

Other Facebooks sites

en espanol: http://www.facebook.com/groups/153010944726588/

cystinuria awareness project: http://www.facebook.com/groups/309167699098336/?fref=ts

Disease Information

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Overview

What is Cystinuria?

Cystinuria is an inherited disease of amino acid transport affecting the absorption of four amino acids from excretory pathways. In all people, cystine, ornithine, lysine and arginine are filtered from the blood into the urine. Normally, those amino acids are reclaimed from the urine for recirculation in the blood. However, cystinuric patients lack the necessary ability to transport those molecules. As a result, they become concentrated in the urine where cystine, being uniquely insoluble, tends to crystallize and form cystine stones. The result is recurring stone formation. These stones can pass spontaneously but larger stones may become stuck in the urinary tract and require surgical intervention for removal. Frequent stone formation, kidney blockage, surgical procedures and resulting consequences can impact kidney function over time.

Who gets Cystinuria?

Cystinuria is a genetic condition passed from parents to children. It is generally accepted that 1 in 10,000 people worldwide are cystinuric. However, as with any genetic disease, the prevalence can vary greatly among communities. As a genetic condition, the disease is present from birth and persists for life. However, symptoms including kidney stone formation, may not occur immediately. While some patients form stones at infancy, others may not be aware of their disease until decades later. Some cystinuric people will never form kidney stones, despite having high urinary cystine concentrations. The underlying cause of why some people seem to be more affected than others is currently unknown.

What causes Cystinuria?

When genes responsible for making specific transport proteins are defective, the transport system fails to transport cystine from the urine. These defective gene copies are inherited from parents and cannot be changed. When cystine cannot be absorbed from the urine, it can concentrate to a point where it forms solid crystals that grow into stones in the urinary tract. Ornithine, arginine and lysine also accumulate in the urine, but are generally soluble even at the elevated concentrations and do not impact the health of the patient.

Diagnosis

Treatments