No, white cats do not have a shorter lifespan although their ears are prone to sunburn and frostbite. I suppose that there may a slightly enhanced risk of a white cat which goes outside a lot getting skin cancer. However, this is not significant enough to say that in general white cats have a shorter lifespan than the average.
The gene that makes the cat white has no health consequences which directly affects the cat’s lifespan. But totally white cats can be deaf and odd-eyed. Clink on this link to read about white cat deafness and this link to see a cat with odd eye color. I have a page on odd-eyed cats here. Once again you might say that if an all-white cat who is deaf is allowed to go outside a lot he is probably more vulnerable to being injured or killed by cars or predators than a hearing cat but also once again I’d argue that this is insignificant as most owners of deaf cats will keep them confined.
Below I discuss how white fur is the lack of pigmentation in the fur. It is not white because there is white pigmentation embedded in the hair strands.
For a cat and perhaps for other creatures white is the absence of pigmentation in the hair strands. The hair is not white because there is white pigmentation in the hair. In short, white is the absence of colour in this instance whereas in an absolute sense white is the merging of all the colours of the visible spectrum. I think that’s quite a nice contrast.
You would have thought that if there is no pigmentation in each hair strand, each strand of hair would be transparent but clearly not. Therefore, the unpigmented hair strand must be opaque to a certain extent and very light in colour.
The reason why there is no pigment in the hair of white cats is because cells which are created very early on during the develop of the foetus inside the womb called melanoblasts – which turn into melanocytes (which are pigment producing cells) – do not migrate from their point of origin to the hair shaft. The point of origin of melanoblasts is the trunk neural crest cells.
The reason why this migration does not take place is because of the white cat carries the white spotting gene or the dominant white gene. In these cats the migration is partly or completely halted.
Because the cell in the skin in which the hair strand is embedded is unable to produce pigment (eumelanin and phaeomelanin) there is no pigment inside the hair strand and therefore looks white.
The white spotting gene is also called the piebald gene and it creates the bicolour cat (white and another color). These genes can cause deafness and odd-eye color.