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Cystinuria

Reviewed January 2009

What is cystinuria?

Cystinuria is a condition characterized by the buildup of cystine crystals or stones in the kidneys and bladder. Cystine is an amino acid, one of the building blocks of proteins. As the kidneys filter blood to create urine, cystine is normally absorbed back into the bloodstream. People with cystinuria cannot properly reabsorb cystine into their bloodstream and the amino acid accumulates in their urine.

As urine becomes more concentrated in the kidneys, the excess cystine forms crystals. As these crystals become larger, they form stones that may lodge in the kidneys or in the bladder. Sometimes cystine crystals combine with calcium molecules in the kidneys to form larger stones. These crystals and stones can create blockages in the urinary tract and reduce the ability of the kidneys to eliminate waste through urine. The stones also provide sites where bacteria may cause infections.

How common is cystinuria?

Cystinuria affects approximately 1 in 10,000 people.

What genes are related to cystinuria?

Mutations in the SLC3A1 and SLC7A9 genes cause cystinuria. The SLC3A1 and SLC7A9 genes provide instructions for making the two parts (subunits) of a transporter protein complex that is made primarily in the kidneys. Normally this protein complex controls the reabsorption of certain amino acids, including cystine, into the blood from the filtered fluid that will become urine. Mutations in either the SLC3A1 gene or SLC7A9 gene disrupt the ability of the transporter protein complex to reabsorb amino acids, which causes them to become concentrated in the urine. As the levels of cystine in the urine increase, the crystals typical of cystinuria form. The other amino acids that are reabsorbed by the transporter protein complex do not create crystals when they accumulate in the urine.

How do people inherit cystinuria?

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

Where can I find information about treatment for cystinuria?

You may find information on treatment or management of cystinuria or some of its symptoms in the links below, particularly the links for MedlinePlus Encyclopedia, Educational resources, and Patient support.

Where can I find additional information about cystinuria?

You may find the following resources about cystinuria helpful. These materials are written for the general public.

  • MedlinePlus - Health information
    • Encyclopedia: Cystinuria (http://www.nlm.nih.gov/medlineplus/ency/article/000346.htm)
    • Encyclopedia: Cystinuria (image) (http://www.nlm.nih.gov/medlineplus/ency/imagepages/17046.htm)
    • Health Topic: Kidney Stones (http://www.nlm.nih.gov/medlineplus/kidneystones.html)
  • Additional NIH Resources - National Institutes of Health
    • National Institute of Diabetes and Digestive and Kidney Diseases: What I need to know about kidney stones (http://kidney.niddk.nih.gov/kudiseases/pubs/stones_ez/)
    • National Institute of Diabetes and Digestive and Kidney Diseases: Your Kidneys and How They Work (http://kidney.niddk.nih.gov/kudiseases/pubs/yourkidneys/index.htm#rate)
  • Educational resources - Information pages
    • Cleveland Clinic: Kidney Stones (http://my.clevelandclinic.org/disorders/kidney_stones/np_overview.aspx)
    • Madisons Foundation (http://www.madisonsfoundation.org/index.php/component/option,com_mpower/diseaseID,269/)
    • Merck Manual Home Edition for Patients and Caregivers (http://www.merck.com/mmhe/sec11/ch146/ch146e.html?&alt=sh)
    • New York Online Access to Health (NOAH): Kidney Stones (http://www.noah-health.org/en/kidver/kidney/specific/stones.html)
    • Orphanet (http://www.orpha.net//consor/cgi-bin/OC_Exp.php?Lng=EN&Expert=214)
  • Patient support - For patients and families
    • CLIMB: Children Living with Inherited Metabolic Diseases (http://www.climb.org.uk/)
    • Family Village (http://www.familyvillage.wisc.edu/lib_cyst.htm)
    • National Organization for Rare Disorders (http://www.rarediseases.org/search/rdbdetail_abstract.html?disname=Cystinuria)
    • University of Kansas Medical Center Resource List (http://www.kumc.edu/gec/support/cystinur.html)

You may also be interested in these resources, which are designed for healthcare professionals and researchers.

  • Gene Tests - DNA tests ordered by healthcare professionals (http://www.genetests.org/query?testid=22232)
  • ClinicalTrials.gov - Linking patients to medical research (http://clinicaltrials.gov/search/condition=%22cystinuria%22)
  • PubMed - Recent literature (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?CMD=search&DB=PubMed&term=(Cystinuria[MAJR])+AND+(cystinuria[TIAB])+NOT+(gene[TIAB])+AND+english[la]+AND+human[mh]&orig_db=PubMed&filters=ON&pmfilter_EDatLimit=1800+Days)
  • Online Books - Medical and science texts
    Scriver's Online Metabolic and Molecular Bases of Inherited Disease (OMMBID): Cystinuria (http://books.mcgraw-hill.com/getommbid.php?isbn=0071459960&template=ommbid&c=191)
  • OMIM - Genetic disorder catalog (http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=220100)

What other names do people use for cystinuria?

  • CSNU

See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.

What if I still have specific questions about cystinuria?

  • See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.
  • Ask the Genetic and Rare Diseases Information Center (http://rarediseases.info.nih.gov/GARD/).
  • Submit your question to Ask the Geneticist (http://www.askthegen.org/).

What glossary definitions help with understanding cystinuria?

acids ; amino acid ; autosomal ; autosomal recessive ; bacteria ; calcium ; cell ; cystine ; gene ; infection ; kidney ; kidney stones ; molecule ; mutation ; protein ; recessive ; sign ; stone ; subunit ; symptom

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://ghr.nlm.nih.gov/glossary).

References
  • Knoll T, Zollner A, Wendt-Nordahl G, Michel MS, Alken P. Cystinuria in childhood and adolescence: recommendations for diagnosis, treatment, and follow-up. Pediatr Nephrol. 2005 Jan;20(1):19-24. Epub 2004 Nov 25. Review. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&dopt=Abstract&list_uids=15602663)
  • Langman CB. The molecular basis of kidney stones. Curr Opin Pediatr. 2004 Apr;16(2):188-93. Review. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&dopt=Abstract&list_uids=15021200)
  • Mattoo A, Goldfarb DS. Cystinuria. Semin Nephrol. 2008 Mar;28(2):181-91. Review. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&dopt=Abstract&list_uids=18359399)
  • Townsend DM, Tew KD, Tapiero H. Sulfur containing amino acids and human disease. Biomed Pharmacother. 2004 Jan;58(1):47-55. Review. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&dopt=Abstract&list_uids=14739061)
  • Trinchieri A, Dormia G, Montanari E, Zanetti G. Cystinuria: definition, epidemiology and clinical aspects. Arch Ital Urol Androl. 2004 Sep;76(3):129-34. Review. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&dopt=Abstract&list_uids=15568305)

 

The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

 
Reviewed: January 2009
Published: May 4, 2009