Mouse models of the USH1 genes (Myo7a, shaker 1; Ush1c, deaf circler; Cdh23, waltzer; Pcdh15, Ames waltzer; Sans, Jackson shaker) exhibit circling behavior, head tossing and profound sensorineural hearing loss, but do not exhibit retinal degeneration [17–23]. Here, PCDH15 is linked to retinal degeneration.