GJB2 and deafness: For example, DFNB1, a main form of GJB2 related deafness,[103, 104] has ubiquitous expression of GJB2 across cochlear supporting cells and lateral wall cells.[102, 105] This ubiquitous expression, coupled with the ectopic expression‐induced ototoxicity in hair cells,[106] requires therapeutic AAV vectors with both broad tropism and stringent GJB2+ cell‐specific targeting.