Albinism

Albinism in cats is usually manifested by white fur, light pink skin and light blue eyes. It is caused by a mutation in the TYR gene encoding tyrosinase, which is key to the production of melanin, the pigment responsible for the colour of the coat, eyes and skin. Melanin also plays a role in the proper development of the retina and visual pathways and protects the skin from UV rays. Due to the absence of melanin, albino cats tend to be sensitive to light.

One of several genetic mechanisms leading to albinism is the nonsense mutation c.1204C>T in the TYR gene, which disrupts the enzymatic activity of tyrosinase so much that it does not allow any melanin production.

The mode of inheritance of the mutation is autosomal recessive. This means that only individuals who inherit the mutated gene from both parents will develop albinism. Carriers ofthe mutated gene are normally coloured but pass the mutation on to their offspring. A genetic test can clearly reveal the genotype of an animal and is a useful tool for breeders in breeding for the desired phenotype.

References:

Abitbol, M., Bossé, P., Grimard, B., Martignat, L., Tiret, L. : Allelic heterogeneity of albinism in the domestic cat. Anim Genet 48:127-128, 2017. Pubmed reference: 27634063