Oct. 25, 2013 -- At age 5, Isaac Brown is learning the alphabet and simple addition. He's also figuring out another vital subject: pain.
Isaac was born with a congenital insensitivity to pain, a disorder that means he almost never feels pain, even if he breaks a bone.
Because he doesn't feel injuries, Isaac's parents, Carrie and Randy Brown, are teaching him how to identify them to stay healthy.
"The toddler years were an absolute nightmare," said Isaac's mother, Carrie Brown. "He would just drop to the ground and smack his face on the table. He thought the fall was fun."
Isaac has dunked his hand in hot coffee without flinching. He once placed his palm on a working oven burner without shedding a tear.
After breaking a cup one time, Isaac banged on his mother's door to get her attention with the broken glass. When Brown opened the door, she found Isaac grasping the sharp edge of the glass. He didn't understand that the broken glass was damaging his hand with each strike.
Although Brown and her husband sought medical help, there is little doctors can do to treat Isaac's condition. After taking Isaac to a specialist, Brown said initially she was told to watch him carefully and bring him in if he appears to be injured.
Looking for relief, the Browns searched the Internet for "children who can't feel pain" and found a Facebook group called The Gift of Pain, where parents talked about their children who had the same disorder as Isaac.
While Isaac's doctors didn't have a lot of day-to-day advice for Brown, the parents in the Facebook group had more detailed instructions about ways to care for Isaac.
"We got a ton of ideas of people who have gone through it," said Brown. "And let me tell you, they have been a gift to us."
One crucial idea was developing ways to "teach" Isaac to recognize pain and possible injuries.
"We're doing the best we can to just teach him; he knows blood is bad," said Brown. "We taught him even when he was little to say 'ow.' You don't have to tell normal kids to say 'ow.'"
Randy Brown accidently stepped on his son's foot once when Isaac was hiding. The boy started giggling, thinking it was a joke because it didn't hurt.
Randy Brown then sat down with him and explained carefully that what happened was bad and that it was an "owie." He also explained that Isaac should always tell a parent if he gets stepped on.
An hour later, Carrie Brown was watching Isaac play.
"Our cat brushed up against him and [Isaac] said, 'Owie, owie, owie,'" said Brown, laughing. Isaac assumed the cat's stepping on him could cause the same injury as his father.
When Isaac broke his pelvis after falling from playground equipment, Brown said he was able to identify something was wrong with his leg even though it took a few x-rays and scans to figure out his pelvis was fractured.
"He does feel [something], but the pain has to be 20 to 30 times greater to what we would feel," said Brown, who explained Isaac couldn't pinpoint what was broken. "He thought his ankle hurt."
In November the family will go to "Camp Painless but Hopeful," a camp related to the Facebook group and that was conceived by the family of Ashlyn Blocker, a 13-year-old girl with the same disorder as Isaac and who made headlines in 2005 for her inability to feel pain.
The first year of the camp eight families attended and Carrie Brown said in the last two years she has come to rely on the parents for help and support. When dealing with such a rare disease Brown said the parents have been crucial resources of information.
Dr. Stephen Waxman, director of the Center for Neuroscience and Regeneration Research at Yale University School of Medicine, said the disease is so rare that doctors do not have a lot of advice on how to deal with it day–to-day and that it makes sense parents might turn to others in the same situation for advice.
"There's not guidelines," for day to day care, said Waxman. "I think we doctors need to work with [these patients] and educate them and we need to learn more about this disorder so in the future we can come up with definitive and effective treatment."
The Brown family is also working with researchers at the Mayo clinic in Rochester, Minn., who are examining Isaac's DNA in the hopes they can uncover which part of Isaac's gene mutated to lead to his insensitivity to pain.
The researchers warned the family it could take between four to eight years to find the mutated gene responsible and there is the possibility that it will never be identified.
Even if researchers identify the gene, it won't cure Isaac.
Waxman describes figuring out the correct mutation of the gene a bit like finding a tiny needle in a giant haystack.
"A gene has many thousands of letters in it. It's like a string of beads," said Waxman. "The sodium channel is a string of 2,000 beads and one of them is wrong. One gene out of 30,000."
Some people with congenital insensitivity to pain have been linked to a specific genetic mutation that affects a specific sodium channel in their nerve cells. When they stub their toe, the neurons that fire to signal pain aren't able to transmit the message through this specific sodium channel and up the spinal cord to the brain. As a result, there is no pain. Since the researchers are still investigating Isaac's genome, it's not confirmed that he has this specific mutation or another version that affected the sodium channel in a different way.
This genetic mutation is incredibly rare and there is little information on how many people are afflicted worldwide. Experts say they estimate about 50 to100 families could carry the mutation worldwide. The disease often results in patients' accidentally self-mutilating because they don't feel the pain that might stop them from scratching their skin raw or biting through their tongue when teething.
Additionally, many people with the disorder, including Isaac, do not sweat, making them incredibly susceptible to heatstroke. Brown said she has to keep Isaac in special cooling vests and does not allow him to be outside in the summer.
Although the disorder has made life difficult for Isaac and his family, researchers believe the genetic mutations that cause the condition could help in the development of breakthrough pain medication.
Scientists and pharmaceutical companies are hoping to imitate the effects of these genetic mutations in order to stop pain signals for people who suffer from chronic pain. If successful, pain medications could potentially "end" debilitating pain without dangerous side effects.
Waxman said if people were able to effectively create pain medication by blocking a specific sodium channel without other side effects, it would be a major medical breakthrough.
"We could fill our clinics five times over with patients in chronic pain," said Waxman.
"The holy grail of pain research is [finding] a type of sodium channel in pain ... that does not play a major role in brain or heart," said Waxman. If researchers could disrupt a specific channel that only transfers pain messages it could possibly mean alleviating pain for those suffering debilitating and chronic conditions.
Last month European researchers published a study in the Nature Genetics journal that revealed they had pinpointed a specific mutation of one gene that caused an unidentified girl to suffer from congenital insensitivity to pain. The girl's mutations lead to a disruption of a specific sodium channel.
Ingo Kuth, a geneticist and co-author of the Nature Genetics study, said he is hoping for the possibility of creating a breakthrough pain medication, but that the research remains in the early stages and scientists have to be careful when developing new medications since "you might avoid [old] side effects, but create new ones."
For Carrie Brown the possibility that Isaac's genetic code could possibly be used to help people is "amazing" and a small silver lining for the family.
"When he was diagnosed, [doctors said] there's nothing we can do for Isaac, not yet anyway," recalled Brown. "But the fact that they can take his mutated gene and cause people with chronic pain to feel less pain. The thought of that is unreal…. God gave us Isaac, maybe for this very purpose."
For now keeping an eye on Isaac has become a duty for all members of the Brown family, and Carrie Brown said it's hard to let Isaac be a kid sometimes.
During a recent play date she took him to a roller rink but quickly took him out of the rink when he fell. Isaac, still wanting to play with his friends told his mother, "It doesn't bother me to fall, Mom. It doesn't bother me!"
Brown turned to her son and said, "I know, but it bothers me."