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SLC7A9 gene

solute carrier family 7 member 9

Normal Function

The SLC7A9 gene provides instructions for producing one part (subunit) of a protein made primarily in the kidneys. This subunit joins with another protein subunit, produced from the SLC3A1 gene, to form a transporter protein complex. During the process of urine formation in the kidneys, this protein complex absorbs particular protein building blocks (amino acids) back into the blood. In particular, the amino acids cystine, ornithine, arginine, and lysine are absorbed back into the blood through this mechanism.

Health Conditions Related to Genetic Changes


At least 95 mutations in the SLC7A9 gene have been found to cause cystinuria. Many of these mutations alter a single DNA building block (nucleotide) or insert or delete a small number of nucleotides in the SLC7A9 gene. These changes lead to an abnormally functioning transporter protein complex, which causes certain amino acids to become concentrated in the urine. Cystine is the only amino acid that forms crystals and stones in the bladder or kidneys, leading to the signs and symptoms of cystinuria.

More About This Health Condition

Other Names for This Gene

  • b0,+AT
  • CSNU3
  • solute carrier family 7 (amino acid transporter light chain, bo,+ system), member 9
  • solute carrier family 7 (glycoprotein-associated amino acid transporter light chain, bo,+ system), member 9
  • solute carrier family 7, member 9

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Gene and Variant Databases


  • Dello Strologo L, Pras E, Pontesilli C, Beccia E, Ricci-Barbini V, de Sanctis L, Ponzone A, Gallucci M, Bisceglia L, Zelante L, Jimenez-Vidal M, Font M, Zorzano A, Rousaud F, Nunes V, Gasparini P, Palacin M, Rizzoni G. Comparison between SLC3A1 and SLC7A9 cystinuria patients and carriers: a need for a new classification. J Am Soc Nephrol. 2002 Oct;13(10):2547-53. doi: 10.1097/01.asn.0000029586.17680.e5. Citation on PubMed
  • Fernandez E, Carrascal M, Rousaud F, Abian J, Zorzano A, Palacin M, Chillaron J. rBAT-b(0,+)AT heterodimer is the main apical reabsorption system for cystine in the kidney. Am J Physiol Renal Physiol. 2002 Sep;283(3):F540-8. doi: 10.1152/ajprenal.00071.2002. Citation on PubMed
  • Font MA, Feliubadalo L, Estivill X, Nunes V, Golomb E, Kreiss Y, Pras E, Bisceglia L, d'Adamo AP, Zelante L, Gasparini P, Bassi MT, George AL Jr, Manzoni M, Riboni M, Ballabio A, Borsani G, Reig N, Fernandez E, Zorzano A, Bertran J, Palacin M; International Cystinuria Consortium. Functional analysis of mutations in SLC7A9, and genotype-phenotype correlation in non-Type I cystinuria. Hum Mol Genet. 2001 Feb 15;10(4):305-16. doi: 10.1093/hmg/10.4.305. Citation on PubMed
  • Font-Llitjos M, Jimenez-Vidal M, Bisceglia L, Di Perna M, de Sanctis L, Rousaud F, Zelante L, Palacin M, Nunes V. New insights into cystinuria: 40 new mutations, genotype-phenotype correlation, and digenic inheritance causing partial phenotype. J Med Genet. 2005 Jan;42(1):58-68. doi: 10.1136/jmg.2004.022244. Citation on PubMed or Free article on PubMed Central
  • Goodyer P. The molecular basis of cystinuria. Nephron Exp Nephrol. 2004;98(2):e45-9. doi: 10.1159/000080255. Citation on PubMed
  • Langman CB. The molecular basis of kidney stones. Curr Opin Pediatr. 2004 Apr;16(2):188-93. doi: 10.1097/00008480-200404000-00013. Citation on PubMed
  • Schmidt C, Vester U, Wagner CA, Lahme S, Hesse A, Hoyer P, Lang F, Zerres K, Eggermann T; Arbeitsgemeinschaft fur Padiatrische Nephrologie. Significant contribution of genomic rearrangements in SLC3A1 and SLC7A9 to the etiology of cystinuria. Kidney Int. 2003 Nov;64(5):1564-72. doi: 10.1046/j.1523-1755.2003.00250.x. Citation on PubMed

The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.