The mutations in TRIC, a gene encoding human tricellulin, were reported to be responsible for hereditary deafness DFNB49 (Riazuddin et al., 2006), and knockin mice mimicking human mutation exhibit deafness associated with progressive hair cell degeneration (Nayak et al., 2013), as observed in Occ−/−, claudin-14 and claudin-9 mutant mice. Here, CLDN9 is linked to deafness.