A NEW drug which has been shown to slow the progression of Huntington's disease has been hailed as the greatest breakthrough since the mutation that causes the genetic illness was first identified 24 years ago.

The experimental drug, injected into spinal fluid, was shown to lower levels of the harmful protein responsible for the incurable killer disease.

There are about 1,100 people in Scotland living with Huntington’s disease in, a disorder that impacts their ability to walk, talk, chew and swallow. More than 5,000 people are estimated to be at risk of developing the hereditary disease.

Current treatments only help with symptoms, rather than slowing the disease’s progression.

But the trial results on Ionis-HTTRx, the first pharmaceutical agent designed to target the root cause of disease have been lauded because it is the first time any drug has been shown to suppress the effects of the Huntington’s mutation that causes irreversible damage to the brain.

The trial involving 46 patients with early-stage Huntington's disease confirmed that the treatment worked as hoped, and was well-tolerated by the participants.

If a bigger next stage trial is successful it is believed the drug could ultimately be used in people with the Huntington’s gene to possibly stopping symptoms ever occurring.

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Lead researcher Professor Sarah Tabrizi, who graduated in biochemistry and medicine at the University of Edinburgh winning the Gold Medal for the most distinguished MBChB graduate said the results were "beyond what I'd ever hope" and that they were of "ground-breaking importance for Huntington's disease patients and families".

She said: "For the first time a drug has lowered the level of the toxic disease-causing protein in the nervous system, and the drug was safe and well-tolerated.

"This is probably the most significant moment in the history of Huntington’s since the gene [was isolated].

"The key now is to move quickly to a larger trial to test whether (the drug) slows disease progressive."

If the future trial is successful, Prof Tabrizi believes the drug could ultimately be used in people with the Huntington’s gene before they become ill, possibly stopping symptoms ever occurring.

“They may just need a pulse every three to four months,” she said. “One day we want to prevent the disease.”

John Eden (below right), chief executive of the Scottish Huntington's Association believed that Scots patients and scientists will be involved in the next trial.

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He said: This is absolutely a momentous breakthrough. It is the first drug shown to directly address the root cause of Huntington’s – the production of the faulty Huntington protein. That’s never been done before.

"It is the moment that families have waited for since the genetic change that causes HD was identified in 1993. For them it has been an impossibly long wait, but this historic announcement makes intangible hope, tangible progress."

Huntington's disease is a progressive neurological disorder that normally appears in middle age and causes involuntary movements, psychiatric symptoms, and dementia. Patients usually die within 20 years after the onset of symptoms.

The new drug, developed by California biotech firm Ionis Pharmaceuticals, contains an "anti-sense" molecule consisting of a single strand of chemically-modified DNA.

The DNA strand stops the genetic instructions for making the Huntington's protein getting through to manufacturing machinery in brain cells.

Levels of the toxic HTT protein involved in Huntington's Disease are reduced, thereby minimising damage to the brain.

Full details of the trial are due to be presented at scientific meetings and published in a peer-reviewed journal next year Dr Philippa Brice, from the genomics research charity PHG Foundation, said: "This is a potential game-changer, not only for Huntington's disease patients but also for genomic medicine in general.

"Though more work needs to be done, if gene silencing lives up to this promise we could be on the brink of some of the personalised treatments that patients with severe genetic diseases need so badly. But this will also raise further questions for society and for policy-makers about how best to use such a powerful technique."