The only types of oculocutaneous albinism (OCA type 1) that have been described in the cat are those associated with mutations on the albino locus of the gene encoding for tyrosinase, which in affected cats leads to inactivity of this enzyme. Recently, the causative mutations for the siamese and burmese temperature-sensitive alleles have been identified in tyrosinase.
OCA type 1 is characterised clinically by complete loss of pigmentation not only of the coat and skin (white coat) but also in retinal and choroidal epithelium in the eye, with associated abnormal optic visual fibres cross over and severe ocular abnormalities (e.g. reduced visual acuity, loss of binocular vision).
White is a common coat color of cats and partial or complete congenital deafness is not uncommon in white cats, especially when one or both irides are blue. Blue-eyed versus pink-eyed albino cats have not been clearly distinguished in the published reports. Thus, it is unclear whether there is more than one non temperature-sensitive albinism allele in cats. Albino cats in a study by Imes et al (2006) had blue eyes. As with most blue-eyed cats, reduced pigment in the tapetum produces a ‘reddish’ (as opposed to a ‘greenish’) tapetal reflection or ‘eye-shine’. The c allele has been reserved for red-eyed (complete) albinism, but the difference in the tapetal reflex suggests that the single report of a red-eyed albino cat may be in error.
Chediak-Higashi syndrome is a rare type of partial oculocutaneous albinism, which is inherited as an autosomal recessive disease and abnormalities include cataracts and decreased pigmentation of the iris and fundus.
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