HTR5A and hearing loss disorder: Plenty of studies demonstrated that 5‐HT pathway played an important role in the auditory function.[45, 46, 47] A clinical study found that the plasma level of 5‐HT was elevated in patients with sensorineural hearing loss (SNHL) and that 5‐HT might appear as a biomarker of SNHL.[48] It also has been reported that 5‐HT 2B receptors are upregulated in age‐related hearing loss.[49] These evidences suggest a critical role for 5‐HT in the pathogenesis of hearing impairment.