In the latest trailer for Netflix’s Luke Cage, the show’s titular protagonist is chastised by his sometime-lover, Claire Temple, for being a coward despite the fact that he can feel no pain. “There’s nothing that can hurt you,” she says accusingly. “So what the hell are you afraid of?” In real life, people who can’t feel pain have the opposite problem: They aren’t afraid of anything.
While Luke Cage makes this seem like a cool thing, the major issue documented in people with the genetic disease known as CIPA — that’s short for “congenital insensitivity to pain with anhidrosis” — is that they don’t immediately perceive pain-inducing things as dangerous. Babies with the genetic defect sometimes chew their lips until they bleed, strip flesh from their fingers while chewing on them, and even bite through their tongues while eating. Adults will burn themselves without noticing or fail to notice fractured bones. By striding confidently into a volley of rapid-fire bullets, Luke Cage, seemingly resolved of his cowardice, is simply doing his best impression of CIPA-afflicted humans.
CIPA is caused by a recessive mutation in a gene involved in the nervous system, and both parents need to pass on a copy of the faulty gene to their child in order for the disorder to manifest. Because nearly half of CIPA-afflicted kids die before they turn three — they actually die from overheating, as the body can’t tell when it’s too hot (hence, “anhidrosis”) — the disease, failing to make it into the adult population, is exceedingly and increasingly rare.
Still, it persists in the human gene pool, and if we needed a real-life explanation for Cage’s ¯_(ツ)_/¯ approach of danger, this would be it.
Of course, even if Cage did have CIPA, he would have one huge advantage over the disorder’s real-life victims: He’s pretty much indestructible, so it doesn’t matter how much pain he fails to perceive. As far as we know, there’s no naturally occurring genetic anomaly that can promise the ability to withstand bullets, but scientists have tried to develop a genetic modification that mimics it: In 2011, Dutch researchers genetically engineered goats to produce milk containing spider silk protein, which was later spun into a skin-like material that could withstand a bullet from a .22 rifle. Merging this “bulletproof skin” with actual skin grown in a petri dish could confer Cage’s ability to dodge bullets and the pain they inflict, at least in theory.
While genetics allows us to propose a hypothesis for Cage’s painlessness, ultimately, it’s emotional, not physical pain, that gets the best of him, and there’s no scientific fix for that. The brooding superhero comes to Netflix on September 30.