Bonsch et al. (2009) reported a 4-generation German family with postlingual onset of nonsyndromic progressive sensorineural hearing loss. Affected individuals had onset in the second to third decade of life of hearing loss first affecting high frequencies and ... Bonsch et al. (2009) reported a 4-generation German family with postlingual onset of nonsyndromic progressive sensorineural hearing loss. Affected individuals had onset in the second to third decade of life of hearing loss first affecting high frequencies and then affecting lower frequencies. The audiogram of older individuals was flat. Four patients reported tinnitus, but none had vestibular signs.