More recent studies have identified the microphthalmia-associated transcription factor gene (MITF) as being a candidate gene for, or closely linked to, the S locus [2, 13, 14], with mutations suppressing melanocytes resulting in variation in the extent of white colour of the coat as well as disrupted function in the stria vascularis leading to cochleo-saccular degeneration and deafness [2, 15]. Here, MITF is linked to deafness.