Re: red heads a form of Albinism?

Makoto Taniguchi wrote:

> Since these people are very weak to the sun and often have thinning
> hair on  their faces such as the mustache/beard and eye brows which is
> a common trait among albinos, are red heads suffering from albinism?

Red hair in humans has been associated with some mutations in Melanocortin
1 receptor (MC1-R).  Red melanin and not black melanin is made, probably
due to decreased signalling from the receptor.  Mutations that make the
receptor constituative cause black melanin to be made.  Knock out
mutations like frame shifts in the receptor gene cause or allow red
pigment to be synthesized.  Red (pheomelanin) melanin doesn't seem to be
as good a sun block as black (eumelanin) melanin.  I don't know if the
facial hair is thinner or just less noticable.  It is not a form of
albinism, but it does decrease the amount of eumelanin produced.

There is an abnormal red hair phentype that is due to the knock out of the
melanocortin ligand for the MC1-R.  No hormone ligand no signal from the
receptor.