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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®


Reviewed February 2007

What is the official name of the USH1C gene?

The official name of this gene is “Usher syndrome 1C.”

USH1C is the gene's official symbol. The USH1C gene is also known by other names, listed below.

What is the normal function of the USH1C gene?

The USH1C gene carries the instructions for the production of a protein called harmonin. Harmonin has the ability to bind to many other proteins in cell membranes and coordinates their activities. Harmonin sometimes acts as a bridge linking proteins in the cell membrane to those in the cytoskeleton, the internal framework that supports the cell.

Research suggests that harmonin plays a role in the development and maintenance of hairlike projections called stereocilia. Stereocilia line the inner ear and bend in response to sound waves. This bending motion is critical for converting sound waves to nerve impulses, an essential process for normal hearing. In the inner ear, protein complexes organized by harmonin probably act as connectors that link stereocilia into a bundle. This protein complex likely helps regulate the transmission of sound waves.

Harmonin is also made in specialized cells called photoreceptors. These cells detect and transfer light energy to the light-sensitive tissue at the back of the eye (the retina). The function of the harmonin-protein complex in the retina is not well understood, but it is thought to be important in the development and function of photoreceptor cells.

How are changes in the USH1C gene related to health conditions?

nonsyndromic deafness - caused by mutations in the USH1C gene

At least one mutation in the USH1C gene causes a form of nonsyndromic deafness (hearing loss without related signs and symptoms affecting other parts of the body) called DFNB18. This mutation changes a single DNA building block (nucleotide), which disrupts the instructions for producing harmonin. The abnormal version of harmonin causes defects in the stereocilia, leading to hearing loss and problems with balance.

Usher syndrome - caused by mutations in the USH1C gene

At least 10 USH1C mutations that cause Usher syndrome type 1C have been identified. One mutation is a common cause of Usher syndrome type 1C in the Acadian population of Louisiana. This mutation changes a single DNA building block (nucleotide) in the USH1C gene, replacing the nucleotide guanine with the nucleotide adenosine at position 216 (written as 216G>A). In other populations, some USH1C mutations insert or delete small amounts of DNA in the gene. Additional mutations disrupt how genetic information from the USH1C gene is spliced together to make a blueprint for producing harmonin. A lack of functional harmonin impairs the normal development of the stereocilia and the retina, leading to the signs and symptoms of Usher syndrome.

Where is the USH1C gene located?

Cytogenetic Location: 11p14.3

Molecular Location on chromosome 11: base pairs 17,493,895 to 17,544,416

The USH1C gene is located on the short (p) arm of chromosome 11 at position 14.3.

The USH1C gene is located on the short (p) arm of chromosome 11 at position 14.3.

More precisely, the USH1C gene is located from base pair 17,493,895 to base pair 17,544,416 on chromosome 11.

See How do geneticists indicate the location of a gene? ( in the Handbook.

Where can I find additional information about USH1C?

You and your healthcare professional may find the following resources about USH1C helpful.

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

What other names do people use for the USH1C gene or gene products?

  • AIE-75
  • Autoimmune enteropathy-related antigen
  • DFNB18
  • NY-CO-37
  • NY-CO-38
  • NY-REN-3 antigen
  • PDZ-45
  • PDZ73
  • PDZ-73
  • PDZD7C
  • Usher syndrome 1C (autosomal recessive, severe)
  • Usher syndrome 1C protein

See How are genetic conditions and genes named? ( in the Handbook.

What glossary definitions help with understanding USH1C?

autoimmune ; autosomal ; autosomal recessive ; cell ; cell membrane ; cytoskeleton ; DNA ; gene ; guanine ; mutation ; nucleotide ; photoreceptor ; population ; protein ; recessive ; retina ; syndrome ; tissue

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.


  • Adato A, Michel V, Kikkawa Y, Reiners J, Alagramam KN, Weil D, Yonekawa H, Wolfrum U, El-Amraoui A, Petit C. Interactions in the network of Usher syndrome type 1 proteins. Hum Mol Genet. 2005 Feb 1;14(3):347-56. Epub 2004 Dec 8. (
  • Ahmed ZM, Riazuddin S, Riazuddin S, Wilcox ER. The molecular genetics of Usher syndrome. Clin Genet. 2003 Jun;63(6):431-44. Review. (
  • Ahmed ZM, Smith TN, Riazuddin S, Makishima T, Ghosh M, Bokhari S, Menon PS, Deshmukh D, Griffith AJ, Riazuddin S, Friedman TB, Wilcox ER. Nonsyndromic recessive deafness DFNB18 and Usher syndrome type IC are allelic mutations of USHIC. Hum Genet. 2002 Jun;110(6):527-31. Epub 2002 May 3. (
  • Blaydon DC, Mueller RF, Hutchin TP, Leroy BP, Bhattacharya SS, Bird AC, Malcolm S, Bitner-Glindzicz M. The contribution of USH1C mutations to syndromic and non-syndromic deafness in the UK. Clin Genet. 2003 Apr;63(4):303-7. (
  • Boëda B, El-Amraoui A, Bahloul A, Goodyear R, Daviet L, Blanchard S, Perfettini I, Fath KR, Shorte S, Reiners J, Houdusse A, Legrain P, Wolfrum U, Richardson G, Petit C. Myosin VIIa, harmonin and cadherin 23, three Usher I gene products that cooperate to shape the sensory hair cell bundle. EMBO J. 2002 Dec 16;21(24):6689-99. (
  • Finsterer J, Fellinger J. Nuclear and mitochondrial genes mutated in nonsyndromic impaired hearing. Int J Pediatr Otorhinolaryngol. 2005 May;69(5):621-47. Review. (
  • Keats BJ, Savas S. Genetic heterogeneity in Usher syndrome. Am J Med Genet A. 2004 Sep 15;130A(1):13-6. Review. (
  • NCBI Gene (
  • Ouyang XM, Xia XJ, Verpy E, Du LL, Pandya A, Petit C, Balkany T, Nance WE, Liu XZ. Mutations in the alternatively spliced exons of USH1C cause non-syndromic recessive deafness. Hum Genet. 2002 Jul;111(1):26-30. Epub 2002 Jun 18. (
  • Petit C. Usher syndrome: from genetics to pathogenesis. Annu Rev Genomics Hum Genet. 2001;2:271-97. Review. (
  • Reiners J, Nagel-Wolfrum K, Jürgens K, Märker T, Wolfrum U. Molecular basis of human Usher syndrome: deciphering the meshes of the Usher protein network provides insights into the pathomechanisms of the Usher disease. Exp Eye Res. 2006 Jul;83(1):97-119. Epub 2006 Mar 20. Review. (
  • Reiners J, van Wijk E, Märker T, Zimmermann U, Jürgens K, te Brinke H, Overlack N, Roepman R, Knipper M, Kremer H, Wolfrum U. Scaffold protein harmonin (USH1C) provides molecular links between Usher syndrome type 1 and type 2. Hum Mol Genet. 2005 Dec 15;14(24):3933-43. Epub 2005 Nov 21. (
  • Savas S, Frischhertz B, Pelias MZ, Batzer MA, Deininger PL, Keats BB. The USH1C 216G-->A mutation and the 9-repeat VNTR(t,t) allele are in complete linkage disequilibrium in the Acadian population. Hum Genet. 2002 Jan;110(1):95-7. Epub 2001 Dec 6. (
  • Siemens J, Kazmierczak P, Reynolds A, Sticker M, Littlewood-Evans A, Müller U. The Usher syndrome proteins cadherin 23 and harmonin form a complex by means of PDZ-domain interactions. Proc Natl Acad Sci U S A. 2002 Nov 12;99(23):14946-51. Epub 2002 Oct 29. (
  • Verpy E, Leibovici M, Zwaenepoel I, Liu XZ, Gal A, Salem N, Mansour A, Blanchard S, Kobayashi I, Keats BJ, Slim R, Petit C. A defect in harmonin, a PDZ domain-containing protein expressed in the inner ear sensory hair cells, underlies Usher syndrome type 1C. Nat Genet. 2000 Sep;26(1):51-5. (


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? ( in the Handbook.

Reviewed: February 2007
Published: November 23, 2015