Isoform-Specific TRIOBP Truncating Variants in Deafness, Autosomal Recessive 28: A Case Study of Postlingual Moderate Sensorineural Hearing Loss

An 18-year-old Italian male was referred to the Audiology Service of AULSS3 Serenissima for evaluation of bilateral nonsyndromic sensorineural hearing loss. He was born to nonconsanguineous parents with normal hearing and had no family history of hearing impairment (Fig. 1, left panel). Pregnancy and perinatal history were unremarkable, with no reported infections or exposure to ototoxic agents. The patient first manifested hearing difficulties during childhood, and audiological follow-up has been ongoing since the age of 8 years. Pure-tone audiometry revealed a moderate, downsloping, bilateral sensorineural hearing loss (pure tone average at 500, 1000, 2000, and 4000 Hz: 44 dB), while the articulation gain curve showed a reduction in speech intelligibility consistent with the degree of hearing loss in both ears. After more than 10 years of follow-up, no progression of hearing loss has been observed to date. No additional abnormalities were noted in his clinical examination or medical history, and, therefore, a genetic etiology was suspected.