Deafness.
Step-by-step explanation
In cats, inherited congenital deafness is seen almost exclusively in white coated individuals. The deafness is caused by degeneration of the auditory apparatus of the inner ear and may affect one or both ears.
The gene responsible is an autosomal dominant gene termed W (for White). This gene appears to be pleiotropic – ie, it has more than one effect, being responsible for the white coat colour and also blue eyes and deafness.