It may sound hard to believe, but some people were actually born without the innate ability to sense pain. It might sound like a dream come true to some people, but it's actually a very dangerous affliction. Without pain, how is your body supposed to know what does and does not hurt you? These people have to approach the world in a different way that most of us wouldn't think twice about. However, these people are in a very small group. In the United States alone, only about 100 people have this rare condition. In Japan, that number triples to around 300.
So how do these people get this disease? Well, it is actually generated through a genetic mutation that presents as either congenital insensitivity to pain (CIP) or congenital insensitivity to pain with anhidrosis (CIPA). Both of these mutations can cause interruption between pain and signaling to the brain. Weirdly, this also applies to temperature. People with these conditions cannot sweat or shiver, because temperature change doesn't really affect them.
If you have CIPA or CIP, you might encounter another few problems. For example, these sufferers often don't have a sense of smell due to the genetic mutation affecting olfactory sensory neurons that transmit smells to our brains. It's also possible that these people will hurt themselves completely by accident and not even realize that they need medical attention, such as getting a broken bone or an unseen cut. Without pain to alert them, they have no way of knowing what is going on with their bodies.
Some of the harder parts of this disease can include chronic bone infections, seizures, recurring high fevers, and much more. The impact this disease has on mental behaviors is another factor in the hardships they endure. Affected individuals often experience weird textures in their skin and hair as well. There is nothing easy about living with this disease, as many can attest. Sadly there is no cure for either CIPA or CIP, but with careful precautionary measures and caretakers, these people can live full and normal lives.