Washington: Eye colour can tell whether you're at risk of serious skin conditions. The blue eyed are less likely to have vitiligo, while the brown eyed may have lower risk of melanoma, says a new study.

Vitiligo is an autoimmune skin disease in which pigment loss results in irregular white patches of skin and hair. Melanoma is the most dangerous kind of skin cancer.

The study, led by the University of Colorado School of Medicine (UCSM), looked at almost 3,000 people with vitiligo of Non-Hispanic European ancestry, identifying 13 new genes predisposed to vitiligo, the journal Nature Genetics reports.

"Genetically, in some ways vitiligo and melanoma are polar opposites. Some of the same genetic variations that make one more likely to have vitiligo make one less likely to have melanoma, and vice-versa," said Richard Spritz, director of the Human Medical Genetics and Genomics Program at the UCSM.

"Vitiligo is an autoimmune disease, in which a person's immune system attacks their normal pigment cells. We think that vitiligo represents overactivity of a normal process by which one's immune system searches out and destroys early cancerous melanoma cells," added Spritz, according to a Colorado statement.

People with vitiligo are at higher risk of various other autoimmune diseases, such as thyroid disease, type 1 diabetes, rheumatoid arthritis and lupus. Their kin are also at higher risk for these same diseases, even if they don't have vitiligo.

Spritz said this means there must be some genes that push towards these autoimmune diseases in general, while other genes and environmental triggers determine which autoimmune disease occurs and when.

So, as scientists learn about the genetics of vitiligo, they are also learning about the genetics of these other autoimmune diseases.