my female cat give birth a 6 beautiful kittens......all are healthy.........2 himalayan and 4 pure white with blue eyed ........but 4 white kittens with blue eyes are deaf by birth ........and my cat again pregnant .......i want to know that what problem with my cat........it is possible next breed with no disability....or always my cat born deaf kittens.........plz plz answer i am very worried about my kittens......