A Single Mutation Is Responsible for Gingers Burning in the Sun

Summer’s coming — which means red heads everywhere are cringing at the prospect of their skin frying from the sun.

Sure, most everyone — regardless of hair color — burns. Even people who never burn build up mutations in their skin when they tan; after all, tanning is the human body’s direct response to mutations triggered by ultraviolet radiation.

But redheads are in extra danger, thanks to a strange quirk of genetics.

One mutation in the gene that regulates pigmentation gives their hair that vivid color and sprinkles them with freckles, while also damaging their skin’s ability to protect itself from the sun’s harsh UV.

Sherrif Ibrahim, a dermatologist and skin cancer expert at the University of Rochester Medical Center, said that, thanks to that mutation, the cells in the skin of redheads do a bad job communicating with each other.

Here’s how that communication mess-up occurs: Everyone has two main types of cells in their skin: keratinocytes and melanocytes. Most of the cells are keratinocytes, which have little in the way of natural defenses against UV. They rely on melanocytes, which dump a protective pigment — melanin — into their neighbors when their neighbors call for help: We’re mutating! We’re mutating!

In most folks, that process works pretty well, Ibrahim said.

“Imagine the finger of the melanocyte extends and knocks on the door of the keratinocyte,” he said. “The keratinocyte has to open up a hole in its membrane to let the melanin in. It knows to do that thanks to a very specific [signal] receptor called the melanocortin 1 receptor.”

But redheads have a mutation to the gene that builds the melanocortin 1 receptor, or MC1R. When the genes in their skin start to mutate under a blast of UV radiation, their protective tanning response breaks down.

Those mutations build up until cells give up on surviving the brief flash of DNA damage and kill themselves to protect that damage from spreading throughout the body.

And that’s what we call a sunburn.

But sunburns aren’t very effective at scouring your body of mutated cells. Some damaged DNA survives — which is a big reason why redheads, who only account for one or two percent of the population, account for a full 16 percent of melanoma. Slather up!