Here are a couple of contrasting examples of feline vitiligo which is a form of leukoderma (white patches in the fur). We see these cats quite a lot nowadays thanks to the explosion of the internet and social media. ‘Leukoderma’ means white skin. Sarah Hartwell, an expert on these conditions and feline genetics tells us that it “usually causes loss of pigment on the face and feet. Antibodies are formed against the pigment-producing melanocytes”.
Melanocytes are cells in the skin where the dark pigment melanin is formed and which migrates to the fur strands. Melanin makes cats black and gives tabby cats their blotches, spots and stripes. In feline vitiligo these pigment producing cells are destroyed which inevitably leads to a loss of pigmentation in the fur causing it to become white. A pattern of white fur can be created.
In the first example we see ‘snowflake’ vitiligo. The pigment loss is seen in patches forming a snowflake appearance which gradually extends to make the coat more white than black.
In the second photo it seems that the patchy removal of pigmentation has resulted in the creation of a distinct pattern somewhat like a tabby pattern. But this is not a tabby coat. It is a black coat with advanced vitiligo in my opinion.
It seems that the snowflake pattern in earlier stage feline vitiligo can develop into stripes.
When the photos of these cats first appeared people believed that the pattern was caused by the same genes that control cat coat patterns such as the tabby pattern. But the cause is not connected with cat coat genetics.
Vitiligo affects humans too. Michael Jackson is the highest profile case. Some wag on Reddit calls cats with this condition “Michael Jackson cats”. Unkind I would say.
The British Skin Foundation say that vitiligo is an autoimmune condition. The body’s immune system rejects the melanocytes leading to antibodies attacking and destroying them. The NHS supports this theory. They say that ‘non-segmental vitiligo’ is caused by an autoimmune condition. Non-segmental vitiligo is when there is some sort of symmetry and a pattern as seen in the second photo.