Hearing loss: a global view for gene therapy approaches and challenges

Hearing loss (HL) is a global issue that affects the quality of life. The incidence of the prelingual form reaches 1: 500 live births, where inherited HL represents the most frequent form. The early diagnosis and intervention to restore hearing might help in reaching near-normal speech milestones in congenital HL cases. Current treatment includes using a hearing aid and cochlear implantation (CI). In spite of the improvement detected on using these treatments, hearing is never back to normal. Gene therapy is the most recent approach studied in an attempt to reach a radical cure for this health problem. The tremendous genetic heterogeneity beyond different types of HL renders gene therapy a challenging yet promising treatment approach. This review encompasses all aspects of this approach including the various strategies (gene-dependent and gene-independent approaches), vehicles used for delivery, routes of administration, drawbacks, and the challenges that remain to be addressed.