Cystinuria

Title

Other Names:

CSNU; Cystinuria-lysinuria

Categories:

Kidney and Urinary Diseases; RDCRN

Summary Summary

Cystinuria is an inherited condition characterized by a buildup of the amino acid, cystine, in the kidneys and bladder. This leads to the formation of cystine crystals and/or stones which may block the urinary tract. Signs and symptoms of the condition are related to the presence of stones and may include nausea, hematuria, flank pain, and/or frequent urinary tract infections. Cystinuria is caused by changes (mutations) in the SLC3A1 and SLC7A9 genes and is inherited in an autosomal recessive manner. The goal of treatment is to relieve symptoms and prevent the formation of stones.^[1]^[2]^[3]

Last updated: 5/12/2015

Symptoms Symptoms

Cystinuria is primarily characterized by a buildup of the amino acid, cystine, in the kidneys and bladder. This leads to the formation of cystine crystals and/or stones which may block the urinary tract. Signs and symptoms of cystinuria are a consequence of stone formation and may include:^[1]^[2]^[3]

Nausea
Blood in the urine (hematuria)
Flank pain
Frequent urinary tract infections
Chronic or acute renal failure (rare)

Last updated: 5/11/2015

The Human Phenotype Ontology (HPO) provides the following list of features that have been reported in people with this condition. Much of the information in the HPO comes from Orphanet, a European rare disease database. If available, the list includes a rough estimate of how common a feature is (its frequency). Frequencies are based on a specific study and may not be representative of all studies. You can use the MedlinePlus Medical Dictionary for definitions of the terms below.

Signs and Symptoms	Approximate number of patients (when available)
Hematuria	90%
Nephrolithiasis	90%
Hyperuricemia	50%
Renal insufficiency	50%
Abnormality of the nervous system	-
Argininuria	-
Autosomal dominant inheritance	-
Autosomal recessive inheritance	-
Cystinuria	-
Hyperlysinuria	-
Ornithinuria	-
Recurrent urinary tract infections	-
Variable expressivity	-

Last updated: 9/1/2016

Cause Cause

Cystinuria is caused by changes (mutations) in the SLC3A1 and SLC7A9 genes. These genes encode a protein complex that helps control the reabsorption of amino acids (such as cystine) in the kidneys. Mutations in these genes disrupt the function of the protein complex, causing cystine to become more concentrated in the urine. As the concentration of cystine increases, cystine crystals and/or stones begin to form in the urinary tract leading to the many signs and symptoms associated with cystinuria.^[4]

Last updated: 5/11/2015

Inheritance Inheritance

Cystinuria is inherited in an autosomal recessive manner. This means that to be affected, a person must have a mutation in both copies of the responsible gene in each cell. The parents of an affected person usually each carry one mutated copy of the gene and are referred to as carriers. Carriers typically do not show signs or symptoms of the condition. When two carriers of an autosomal recessive condition have children, each child has a 25% (1 in 4) risk to have the condition, a 50% (1 in 2) risk to be a carrier like each of the parents, and a 25% chance to not have the condition and not be a carrier.^[4]

Last updated: 5/11/2015

Diagnosis Diagnosis

Screening for cystinuria should be considered in people with recurrent or bilateral (i.e. affecting both kidneys) stones; those who develop stones at an early age (before age 30); and people who have a family history of cystinuria. A diagnosis is typically made after an episode of kidney stones when testing reveals that the stones are made of cystine.^[1]^[2]^[3]

The following tests may be recommended to detect kidney stones and diagnose cystinuria:^[1]^[2]^[3]

24-hour urine collection
Abdominal imaging (CT scan, MRI, or ultrasound)
Intravenous pyelogram (IVP)
Urinalysis
Genetic testing

Last updated: 5/11/2015

Testing Resources

The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.

Treatment Treatment

Treatment of cystinuria is focused on relieving symptoms and preventing the formation of additional stones. A more conservative approach is typically tried first. This may include increasing fluid intake, regular monitoring of urinary pH, dietary restrictions (i.e. eating less salt) and increasing the pH of urine with potassium citrate supplements. If these strategies do not prevent the formation of stones, medications may be added to help dissolve the cystine crystals.^[1]^[2]^[3]

Treatment for cystinuria-related stones varies depending on the size and location of the stone, but may include:^[1]^[2]^[3]

Extracorporeal shock wave lithotripsy (ESWL)
Ureteroscopy
Percutaneous nephrolithotomy
Open surgery (in rare cases)

Medscape Reference's Web site offers more specific information regarding the treatment and management of cystinuria. Please click on the link to access this resource.

Last updated: 5/12/2015

FDA-Approved Treatments

The medication(s) listed below have been approved by the Food and Drug Administration (FDA) as orphan products for treatment of this condition. Learn more orphan products.

Tiopronin (Brand name: Thiola®) - Manufactured by Retrophin, Inc.
FDA-approved indication: Prevention of cystine nephrolithiasis in patients with homozygous cystinuria.
National Library of Medicine Drug Information Portal

Prognosis Prognosis

Cystinuria is a chronic condition and many affected people experience recurrent cystine stones in the urinary tract (kidneys, bladder and ureters). In rare cases, frequent kidney stones can lead to tissue damage or even kidney failure.^[1]^[2]

Last updated: 5/12/2015

Research Research

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

ClinicalTrials.gov lists trials that are studying or have studied Cystinuria. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

Patient Registry

The Rare Kidney Stone Consortium is a team of doctors, nurses, research coordinators, and research labs throughout the U.S., working together to improve the lives of people with primary hyperoxaluria, cystinuria, dihydroxyadeninuria, and Dent's disease through research. The Rare Kidney Stone Consortium has a registry for patients who wish to be contacted about clinical research opportunities.

Organizations Organizations

Nonprofit support and advocacy groups bring together patients, families, medical professionals, and researchers. These groups often raise awareness, provide support, and develop patient-centered information. Many are the driving force behind research for better treatments and possible cures. They can direct people to research, resources, and services. Many groups also have experts who serve as medical advisors. Visit their website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD. Suggest an organization to add.

Organizations Supporting this Disease

American Kidney Fund, Inc.
6110 Executive Boulevard
Suite 1010
Rockville, MD 20852
Toll-free: 800-638-8299
Telephone: 301-881-3052
E-mail: helpline@kidneyfund.org
Website: http://www.kidneyfund.org
Cystinuria Support Network
22814 NE 21st Place
Redmond, WA 98053
Telephone: 425-868-2996
E-mail: sue@cystinuria.com
Website: http://www.cystinuria.com/
International Cystinuria Foundation
302 Belview Court
Longmont, CO 80501-4779
Website: http://cystinuria.org/
National Kidney Foundation
30 East 33rd Street
New York, NY 10016
Toll-free: 800-622-9010
Telephone: 212-889-2210
Fax: 212-689-9261
E-mail: http://www.kidney.org/about/contact.cfm
Website: http://www.kidney.org

Social Networking Websites

Visit the International Cystinuria Foundation's group on Facebook.

Living With Living With

Living with a genetic or rare disease can impact the daily lives of patients and families. These resources can help families navigate various aspects of living with a rare disease.

Genetics Resources

To find a medical professional who specializes in genetics, you can ask your doctor for a referral or you can search for one yourself. Online directories are provided by GeneTests, the American College of Medical Genetics, and the National Society of Genetic Counselors. If you need additional help, contact a GARD Information Specialist. You can also learn more about genetic consultations from Genetics Home Reference.

Learn More Learn More

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

Genetics Home Reference (GHR) contains information on Cystinuria. This website is maintained by the National Library of Medicine.
MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

In-Depth Information

Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine.
Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
PubMed is a searchable database of medical literature and lists journal articles that discuss Cystinuria. Click on the link to view a sample search on this topic.

News & Events News & Events

GARD Answers GARD Answers

If you would like to submit a question, please contact GARD

References References

Cystinuria. MedlinePlus. October 2013; http://www.nlm.nih.gov/medlineplus/ency/article/000346.htm.
Chandra Shekhar Biyani, MBBS, MS, DUrol, FRCS(Urol), FEBU. Cystinuria. Medscape Reference. April 2015; http://emedicine.medscape.com/article/435678-overview.
Saravakos P, Kokkinou V, Giannatos E. Cystinuria: current diagnosis and management. Urology. April 2014; 83(4):693-699.
Cystinuria. Genetics Home Reference. June 2014; http://www.ghr.nlm.nih.gov/condition/cystinuria.