Hereditary hearing loss is the most common inherited sensory defect, affecting about 1 per 1000 children. With the advances in molecular genetics, the nature of hereditary hearing loss has started to be unraveled. A plethora of deafness genes were discovered in the past years, and among them certain genetic mutations were noted to be extraordinarily popular in the hearing-impaired population. For example, mutations in the SLC26A4 gene have been documented with high prevalence in a variety of ethnic backgrounds, including Caucasians, Japanese and Han Chinese.