Clinical Medicine Insights: Ear, Nose and Throat

Retinoic acid is an indispensable regulator of inner ear development. However, in either excess or deficiency, retinoic acid acts as a potent teratogen. Pathological effects produced in the inner ear by aberrant retinoic acid conditions lead to impaired functionality. This article will provide an overview of critical components of the retinoic acid signaling pathway, and demonstrate how changes in retinoid signaling affect otic development, with particular emphasis on the inner ear. The downstream targets of retinoic acid signaling and the implications of their misexpression to otic morphogenesis are discussed.