Maltese dilution of domestic cats. A generalized cutaneous albinism lacking ocular involvement.

The Maltese dilution is an autosomal recessive trait of cats that dilutes black cats to blue, and orange cats to cream. The pigmented cutaneous and ocular tissues of Maltese dilution and control cats were examined and compared by light microscopy. Most of the melanin granules in all of the pigmented cutaneous tissues of the Maltese dilution cats were aggregated together into large clumps. However, none of the intraocular tissues containing melanin producing cells of either neural crest or optic cup embryologic origin contained clumped melanin granules. It is concluded that the Maltese dilution trait is a unique generalized albinism without ocular involvement.