News & Events October 22, 2019

Perth team synthesises missing enzyme in rare genetic condition that makes exercise hurt.

Exercise can be painful for anyone who pushes themselves hard enough, but for people suffering McArdle’s Disease, simply walking upstairs, lifting up a child or running for the bus can cause significant pain in their working muscles.

The reason is that the sugar needed by the muscle to provide energy isn’t able to be accessed. Instead it just sits in pockets within the muscle. The muscle’s inability to access sugar results in very painful muscle cramps, muscle damage and the muscle breaking down.

On rare occasions, if there’s a large amount of muscle breakdown, people can also suffer kidney damage.

People with McArdle’s Disease usually experience symptoms in their early 20’s. Diagnosis can be confirmed by a muscle biopsy or by taking a DNA sample.

Dr Rhonda Taylor of the Neurogenetic Diseases Laboratory at the Harry Perkins Institute of Medical Research in Perth says the condition was first diagnosed in the early 1950s but to date no treatment or cure has been discovered.

“The disease is caused by a mutation in a particular enzyme which helps with the breakdown of sugar.”

She said the Perth team synthesised the missing enzyme and developed a way to deliver it to the muscle cells.

“The novel part we’ve developed is in how you deliver it. We wanted to target it to the muscle and not have it affecting every other tissue.

“Genes have a segment of DNA which tells them when to turn on and off and that’s called a promoter and we’ve included a muscle specific promoter to target where it is expressed.

“This is the first of its kind, the first application of gene therapy to McArdle’s Disease,” she said.

The team’s research was recently published in the journal ‘Human Molecular Genetics’.

A treatment for patients is likely to take years before becoming available.