Cochlear nerve canal stenosis: Association with the TECTA gene

Cochlear nerve canal stenosis is characterized by a cochlear nerve canal measured to be less than 1.5mm on high resolution computerized tomography (HRCT) of the temporal bones. Previous studies have demonstrated that stenosis of the cochlear nerve canal has an appreciable impact on the development of the cochlear nerve. Cochlear nerve dysplasia has been identified as a cause of sensorineural hearing loss. We identify a pediatric case in which cochlear nerve canal stenosis presented alongside a potentially pathogenic mutation in the TECTA gene. We report a seven-year-old girl with non- syndromic congenital sensorineural hearing loss with accompanying left sided cochlear nerve canal stenosis and no family history of hearing loss. Upon genetic testing, a heterozygous mutation of the TECTA gene was found (c.112delA (p.T38Pfs*4)), known to be associated with sensorineural hearing loss . The mother was found to have shared the mutation while the father did not. CNCS is most often reported to be associated with the mutations MYH9 and MYH14. We demonstrate a case in which a mutation in the TECTA gene, which encodes α-tectorin, an important component to the non-collagenous glycoprotein profile of the tectorial membrane, presented with severe unilateral cochlear nerve canal stenosis and sensorineural hearing loss. This case provides possible pathogenic evidence for the role of mutations in the TECTA gene in the development of early sensorineural hearing loss.