Four turned out to be atypical Usher syndrome: adult-onset mild neurosensorial hearing loss (RP-1735, RP-1979, RP-0338 and RP-0344 with mutations in USH2A) and one cone-rod dystrophy (CRD) (RP-1543 with mutations in ABCA4). This evidence concerns the gene USH2A and cone-rod dystrophy.