Red hair, fair skin, sun exposure, and MS

An Australian study of 136 MS subjects and 272 controls has found connections between red hair-conferring genes, fair skin, sun exposure, and risk of MS. In this study, people with gene variants that result in red hair were more likely to have avoided sun exposure, and women with these variants (but not men) had an increased risk of MS.

People without these variants who had had lower sun exposure as a child had an increased risk of MS. In past studies, low levels of vitamin D, which can be generated through sunlight exposure, have been associated with increased MS risk, which may explain these results. This may be an example where a genetic association with MS (red-hair variants) may come about through changed behavior (sun avoidance) rather than the direct activity of the gene.