Monday, 31 October 2016

Superpowers? (1) Feeling no pain

Our brains are complex and perform a multitude of different actions and functions simultaneously. It's unlikely that we will ever fully understand exactly how our brains do work, although research into our brain's inner workings is continually ongoing.

One thing we do know is that sometimes our brains don't function correctly. We all have seen or read of the devastating and debilitating effects this can have, but some people are able to live a relatively normal life in spite of their affliction. In this new series of blog posts I will be exploring some of the more unusual disorders, affecting both the brain and body. The conditions covered can grant a patient with abilities that might appear as a positive from the outside, but, as we will discover, can have a much darker reality.

This week will be looking at congenital analgesia, also known as congenital insensitivity to pain. This is when a person cannot feel physical pain. Although the condition sounds fictional, like a superpower in a movie, it is actually extremely dangerous. Not having a sense of pain can lead to accidentally inflicting serious injuries or even an early death. 

Interestingly, people with this condition are able to feel other tactile sensations - for example, they can determine where on their arm someone is touching them, as well as different temperatures - but no pain. Young children and babies with the condition can hurt themselves unintentionally by chewing their tongues or cheeks, which is often used as evidence for the initial diagnosis. As they grow up, more precautions must be taken against being burned by hot objects or accidental scratches and bruises, for example.

Genetics research may help to develop treatments for the condition
Source: The Guardian/Alamy
One example of someone with this condition is Steven Pete. The 33-year-old from the US has broken his bones more than 70 times, but often doesn't realise he has until someone else points it out. He was in and out of hospital often as a child, almost always wearing casts for various injuries. At one point Steven was put into care, as someone reported his parents for child abuse, not realising his condition meant he often unintentionally would injure himself. Now an adult, he describes himself as "not a particularly reckless person", but worries about internal injuries as he has no way of noticing them. However, Steven says that although his brain can't process pain, he believes he can feel his body trying to heal from injuries or illness. He says "it's not pain I deal with, it's extreme discomfort". He visits the hospital regularly for check ups to be safe. Around 1 in every million people are born with the condition.

Recent research has discovered that use of the opioid antagonist drug Naloxone can be used to help patients feel pain again. One study last year allowed a woman with congenital insensitivity to pain to experience pain for the first time. It may sound counter-intuitive to want to feel pain, but for patients with the condition it can really be a life-saver. 

Researchers have also recently discovered a genetic cause of the condition. Scientists found mutations in a gene called PRDM12 in a study of 11 affected families across Europe and Asia. The research found that mutations in both of the copies of the gene that a person inherits (1 copy from the mother, 1 copy from the father) can lead to all pain sensors in the body being turned off at birth. A few other gene mutations have previously been identified in connection with the condition (such as SCN9A mutations), which contribute to pain nerves not functioning correctly.

Research into the SCN9A mutations and Steven's condition are described in the clip below from the Science Museum's Painless exhibition series:


By working out the genetic cause, researchers may be able to better understand the nature of the condition and pain itself. The information gained could also help those who suffer from chronic pain. For those with the condition like Steven, this research must continue.

If you'd like to learn more, please click here (Steven's story in more depth, BBC) and here (The Independent).


3 comments:

  1. Truly the brain is an untapped and unexplored resource.

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  2. I've heard about people who cannot feel pain and initially it sounds like a dream until you delve into what that actually means. You then realise how complex the human body is.

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  3. A truly painless read. I found especially fascinating the idea of using an “opioid antagonist” (Naloxone) as an effective measure to counteract the disease. Does this imply that congenital analgesia functions in the same way as an opioid like morphine: by binding to opioid receptors and inhibiting other (proteins?) from communicating senses like pain to the nervous system? Or, since ‘congenital’ implies from birth, does the disease instead disable the receptor itself from being constructed?

    And since the word ‘congenital’ implies from birth, does this mean that one cannot incur non-congenital analgesia? In other words, are we who are born without insensitivity to pain safe from ever acquiring the disease itself?

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