Cochlin is a protein that in humans is encoded by the COCHgene.[5][6] It is an extracellular matrix (ECM) protein highly abundant in the cochlea and vestibule of the inner ear, constituting the major non-collagen component of the ECM of the inner ear.[7][8] The protein is highly conserved in human, mouse, and chicken, showing 94% and 79% amino acid identity of human to mouse and chicken sequences, respectively.[6]
The gene is expressed in spindle-shaped cells located along nerve fibers between the auditory ganglion and sensory epithelium. These cells accompany neurites at the habenula perforata, the opening through which neurites extend to innervate hair cells. This and the pattern of expression of this gene in chicken inner ear paralleled the histologic findings of acidophilic deposits, consistent with mucopolysaccharide ground substance, in temporal bones from DFNA9 (autosomal dominant nonsyndromic sensorineural deafness 9) patients. Mutations that cause DFNA9 have been reported in this gene.[6]
Cochlin has been identified in the trabecular meshwork (TM) of glaucoma patients, but not in healthy controls. The TM is a filter like area of tissue in the eye; cochlin may have a role in cell adhesion, mechanosensation, and modulation of the TM filter.[10][11]
^Robertson NG, Skvorak AB, Yin Y, Weremowicz S, Johnson KR, Kovatch KA, Battey JF, Bieber FR, Morton CC (December 1997). "Mapping and characterization of a novel cochlear gene in human and in mouse: a positional candidate gene for a deafness disorder, DFNA9". Genomics. 46 (3): 345–54. doi:10.1006/geno.1997.5067. PMID9441737.
^Ikezono T, Omori A, Ichinose S, Pawankar R, Watanabe A, Yagi T (March 2001). "Identification of the protein product of the Coch gene (hereditary deafness gene) as the major component of bovine inner ear protein". Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease. 1535 (3): 258–65. doi:10.1016/s0925-4439(00)00101-0. PMID11278165.
Khetarpal U, Schuknecht HF, Gacek RR, Holmes LB (September 1991). "Autosomal dominant sensorineural hearing loss. Pedigrees, audiologic findings, and temporal bone findings in two kindreds". Archives of Otolaryngology–Head & Neck Surgery. 117 (9): 1032–42. doi:10.1001/archotol.1991.01870210104022. PMID1910721.
Robertson NG, Khetarpal U, Gutiérrez-Espeleta GA, Bieber FR, Morton CC (September 1994). "Isolation of novel and known genes from a human fetal cochlear cDNA library using subtractive hybridization and differential screening". Genomics. 23 (1): 42–50. doi:10.1006/geno.1994.1457. PMID7829101.
Khetarpal U (January 1993). "Autosomal dominant sensorineural hearing loss. Further temporal bone findings". Archives of Otolaryngology–Head & Neck Surgery. 119 (1): 106–8. doi:10.1001/archotol.1993.01880130108016. PMID8417734.
Grabski R, Szul T, Sasaki T, Timpl R, Mayne R, Hicks B, Sztul E (October 2003). "Mutations in COCH that result in non-syndromic autosomal dominant deafness (DFNA9) affect matrix deposition of cochlin". Human Genetics. 113 (5): 406–16. doi:10.1007/s00439-003-0992-7. PMID12928864.
Lemaire FX, Feenstra L, Huygen PL, Fransen E, Devriendt K, Van Camp G, Vantrappen G, Cremers CW, Wackym PA, Koss JC (September 2003). "Progressive late-onset sensorineural hearing loss and vestibular impairment with vertigo (DFNA9/COCH): longitudinal analyses in a belgian family". Otology & Neurotology. 24 (5): 743–8. doi:10.1097/00129492-200309000-00009. PMID14501450.
Usami S, Takahashi K, Yuge I, Ohtsuka A, Namba A, Abe S, Fransen E, Patthy L, Otting G, Van Camp G (October 2003). "Mutations in the COCH gene are a frequent cause of autosomal dominant progressive cochleo-vestibular dysfunction, but not of Meniere's disease". European Journal of Human Genetics. 11 (10): 744–8. doi:10.1038/sj.ejhg.5201043. PMID14512963.
