POU3F4 and deafness: Lack of POU3F4 expression in the development of the mouse inner ear leads to a defective adhesion of the fibrocytes in the spiral ligament and consequent degeneration of Cx26/Cx30 gap junction plaques in the inner sulcus (Kidokoro et al., 2014), thus explaining the loss of the endocochlear potential and deafness in Pou3f4-deficient mice.