Here's a story about blue skinned people.

Blue-skinned Fugate family of Kentucky, who were blue for genetic reasons. The blue skinned members of this family are traced to a genetic mutation that occurred when a French orphan Martin Fugate married fair-skinned, red-headed American Elizabeth Smith in the 1800s. Some of their children suffered from a condition called methemoglobinemia, which “reduces individual’s ability to carry oxygen in blood.” The Fugates remained in an isolated part of Appalachian, and intermarried with a neighboring family, which preserved the mutation, but kept it only in their gene pool.

There was talk of the Appalachian Blue men for a while, but doctors first became aware of the Fugates and their condition when descendent Luke Combs took his wife to the University of Kentucky Hospital in 1958, and the medical staff paid more attention to him than his sick wife. “Luke was just as blue as Lake Louise on a cool summer day,’ doctor Charles H. Behlen II told the Tri-City Herald in 1974.

The mutation didn’t seem to show any medical problems despite the reduced oxygen in the blood, and they found that, oddly enough, when people with the mutation drank a special blue drink it actually turned their blood a normal color, but they had to drink the solution every day to keep it up. People still have the recessive met-H gene, but it appears much less often now that the Fugate descendants are no longer isolated and intermarrying, and are therefore introducing more genes into their gene pool.