Deafness in Dalmatians does not appear to be dominant since deaf puppies result from hearing parents. These findings might be explained by a polygenic cause, the presence of two different autosomal recessive deafness genes, or a syndrome with incomplete penetrance. Deafness is still clearly linked to the extreme piebald gene in Dalmatians. Blue eyes are allowed in the breed standard of the United States, but not in Canada or Europe. Vestibular system signs, including head tilt and circling, are seen, and the deafness is transmitted by a simple autosomal recessive mechanism.
Numerous references report that most congenital deafness in dogs is autosomal recessive.
However, the available data suggest that this is not true for most breeds. Cats carrying the W gene are not always solid white, often having colored spots on their heads that may disappear with age. Whether the cat is heterozygous or homozygous for W, the blue eyes and deafness have incomplete penetrance.