Around 40% of cats with white fur and blue eyes are deaf.
The gene responsible is pleiotropic means that one gene responsible for their deafness controls and affects multiple unrelated characteristics.
Pleiotropic gene action is what occurs when one gene affects two or more unrelated phenotypic characteristics or traits. An example of pleiotropic gene action occurs in Marfan syndrome (a human hereditary disorder). Marfan syndrome is caused as a result of a mutation in one gene which affects multiple features in the growth and development aspects such as height and the heart function.
