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SUOX gene

sulfite oxidase

Normal Function

The SUOX gene provides instructions for making an enzyme called sulfite oxidase, which helps break down protein building blocks (amino acids) that contain sulfur when they are no longer needed. Specifically, sulfite oxidase is involved in the final step of this process, in which sulfur-containing molecules called sulfites are converted to other molecules called sulfates by adding an oxygen atom (a process called oxidation).

Health Conditions Related to Genetic Changes

Isolated sulfite oxidase deficiency

At least 27 SUOX gene mutations have been identified in people with isolated sulfite oxidase deficiency (ISOD), a severe disorder that causes brain damage and is generally fatal in the first months or years of life. The SUOX gene mutations that cause ISOD impair the function of sulfite oxidase, preventing complete breakdown of sulfur-containing amino acids. As a result, sulfites and other compounds left over from the partial breakdown process abnormally accumulate in the body. Researchers suggest that the nervous system is especially sensitive to this abnormal accumulation, and excessive levels of sulfite compounds that are toxic to the brain are thought to result in the brain damage that occurs in ISOD.

More About This Health Condition

Polycystic ovary syndrome

MedlinePlus Genetics provides information about Polycystic ovary syndrome

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Other Names for This Gene

  • sulfite oxidase, mitochondrial

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Catalog of Genes and Diseases from OMIM

Gene and Variant Databases


  • Bindu PS, Nagappa M, Bharath RD, Taly AB. Isolated Sulfite Oxidase Deficiency. 2017 Sep 21. In: Adam MP, Feldman J, Mirzaa GM, Pagon RA, Wallace SE, Bean LJH, Gripp KW, Amemiya A, editors. GeneReviews(R) [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2024. Available from Citation on PubMed
  • Claerhout H, Witters P, Regal L, Jansen K, Van Hoestenberghe MR, Breckpot J, Vermeersch P. Isolated sulfite oxidase deficiency. J Inherit Metab Dis. 2018 Jan;41(1):101-108. doi: 10.1007/s10545-017-0089-4. Epub 2017 Oct 4. Citation on PubMed
  • Karakas E, Kisker C. Structural analysis of missense mutations causing isolated sulfite oxidase deficiency. Dalton Trans. 2005 Nov 7;(21):3459-63. doi: 10.1039/b505789m. Epub 2005 Sep 26. Citation on PubMed
  • Karakas E, Wilson HL, Graf TN, Xiang S, Jaramillo-Busquets S, Rajagopalan KV, Kisker C. Structural insights into sulfite oxidase deficiency. J Biol Chem. 2005 Sep 30;280(39):33506-15. doi: 10.1074/jbc.M505035200. Epub 2005 Jul 27. Citation on PubMed
  • Tan WH, Eichler FS, Hoda S, Lee MS, Baris H, Hanley CA, Grant PE, Krishnamoorthy KS, Shih VE. Isolated sulfite oxidase deficiency: a case report with a novel mutation and review of the literature. Pediatrics. 2005 Sep;116(3):757-66. doi: 10.1542/peds.2004-1897. Erratum In: Pediatrics. 2005 Dec;116(6):1615. Citation on PubMed
  • Zaki MS, Selim L, El-Bassyouni HT, Issa MY, Mahmoud I, Ismail S, Girgis M, Sadek AA, Gleeson JG, Abdel Hamid MS. Molybdenum cofactor and isolated sulphite oxidase deficiencies: Clinical and molecular spectrum among Egyptian patients. Eur J Paediatr Neurol. 2016 Sep;20(5):714-22. doi: 10.1016/j.ejpn.2016.05.011. Epub 2016 May 30. Citation on PubMed or Free article on PubMed Central

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