Acquaintances say Adam Lanza was insensitive to pain. Barbara Frey / AP Richard Novia, who headed the high school technology club of which Lanza was a member, told the AP, "If that boy would've burned himself, he would not have known it or felt it physically. It was my job to pay close attention to that." An unnamed family friend said, “A few years ago when he was on the baseball team, everyone had to be careful that he didn’t fall because he could get hurt and not feel it." And family friend Ellen Adriani told the New York Post that Lanza's mother "was teaching him to cut up fruit. Because he couldn’t feel any pain, he had to be careful with the knife.” None of Lanza's family members or doctors have yet confirmed these accounts. Congenital insensitivity to pain is caused by nerve abnormalities. Oguz Aral / Via shutterstock.com People with the disorder can feel touch, but not pain (some cannot feel extreme temperatures). Abnormalities in specific nerve fibers that transmit pain stimuli appear to be the cause. Some patients also have anhidrosis, an inability to sweat. In some cases, the nerve abnormalities appear to be caused by problems with a particular gene governing pain — other abnormalities in this gene can cause extreme pain disorders. It affects just 1 in 25,000 children. vladm / Via shutterstock.com That's one estimate. Other studies simply describe it as "rare." Tara Blocker, whose daughter Ashlyn has the disorder and was recently profiled by the New York Times, says she was told "we were the only ones out there." It can be dangerous. Melianiaka Kanstantsin / Via shutterstock.com Children with congenital insensitivity to pain can cut or burn themselves without knowing it. One Israeli boy with the disorder had to have his leg amputated after he hurt himself and the wound became infected. Some patients can also get heat stroke due to their inability to sweat. It's not related to a lack of empathy. szefei / Via shutterstock.com Several studies have examined whether people with congenital insensitivity to pain are able to understand and empathize with others' pain. The answer: yes. In one study, people with CIP were able to tell if someone else was in pain by their facial expression, even though they'd never felt pain themselves. The study authors wrote that "a normal personal experience of pain is not necessarily required for perceiving and feeling empathy for others' pain." Some patients experience cognitive or emotional effects, but others do not. dotshock / Via shutterstock.com Some patients with congenital insensitivity to pain can also experience cognitive delays, and some sources link the condition with "hyperactivity or emotional instability." However, many patients, like Ashlyn Blocker, do not present any psychological issues. There's currently no cure, but some interventions can help. Yuri Arcurs / Via shutterstock.com Doctors haven't figured out if it's possible to fix the nerve abnormalities involved in congenital insensitivity to pain. But clinicians do recommend mouth guards for some patients to keep them from biting their lips or cheeks. Other recommendations include counseling and monitoring of skin for any cuts or burns that the patient may not notice. Ashlyn Blocker, who has congenital insensitivity to pain, helped start Camp Painless But Hopeful, where kids with congenital insensitivity to pain and their families can meet and learn from each other.