Family cannot feel pain due to rare genetic mutation

Members of an Italian family with an unusually low sensitivity to pain have had their DNA analysed to locate the genetic basis of their condition.

The scientists who conducted the study hope understanding the condition, which six members of the Marsili family have, will help develop more effective painkillers.

Affected family members can suffer burns and broken bones while feeling virtually no pain, meaning they often do not notice injuries.

The results of the study were published in the journal Brain.

“The grandmother, she came off an escalator and broke her ankle,” said Dr James Cox, a geneticist at University College London and one of the co-authors of the study documenting the discovery.

“She went to the doctor, who took her X-ray and said ‘well actually you’ve broken your ankle before’.”

The research team identified that the Marsilis do possess the nerves in their bodies that should allow them to feel pain, which suggested their condition was genetic.

“We have spent several years trying to identify the gene that is the cause of this,” said Dr Cox.

Using DNA from blood samples, Dr Cox and his colleagues found a mutation in a gene called ZFHX2.

When the researchers removed the same gene in mice, they found the mice were resilient to pain, just like the Marsilis. Providing mice with the same mutated gene version the family members have also reduced pain sensitivity.

“This particular disorder may only be in one family,” said Dr Cox.

While the gene mutation is very rare, the researchers say understanding it has wider implications.

"By identifying this mutation and clarifying that it contributes to the family's pain insensitivity, we have opened up a whole new route to drug discovery for pain relief,” said co-author Professor Anna Maria Aloisi of the University of Siena, a member of the team that first came across the Marsilis’ condition.

Specifically, Dr Cox and his colleagues hope their work will help develop treatments that can be used by people living with chronic pain.

"We hope that our findings and the subsequent research projects will help find better treatments for the millions of people worldwide who experience chronic pain and don't get relief from existing drugs," said the study's first author, Dr Abdella Habib of Qatar University.