In addition, given the similarity of stereocilia bundle defects in Grxcr2 mutants with those described in mice carrying mutations in Usher genes [64], we also screened 120 index cases diagnosed with Usher syndrome, a recessive disorder that combines hearing loss with visual defects caused by retinitis pigmentosa [65]: 21 cases with type I, 47 cases with type II, 5 cases with type III, 4 cases with atypical and 43 cases with uncharacterized Usher syndrome. Here, GRXCR2 is linked to Usher syndrome.