An autosomal dominant inherited disorder known as DFNA8/12 causes mild-to-moderate/severe mid-frequency or mild-to-severe progressive high-frequency sensorineural hearing impairment. The causative gene, TECTA, encodes alpha-tectorin, the most important non-collagenous component of the tectorial membrane in the cochlea and the otolith membrane in the maculae of the vestibular system. Mutations in the zona pellucida domain of alpha-tectorin cause mid-frequency hearing impairment, whereas mutations in the zonadhesin domain cause progressive high-frequency hearing impairment. The intact hearing in the low and high frequencies may prohibit successful correction with a hearing aid.