Huntington’s disease has long been seen as one of the worst conditions anyone can face. It has features of dementia, psychosis and motor neurone disease — a modern-day nightmare. But for the first time in history, scientists are on the verge of changing that story. A real treatment, and possibly even a cure, is in sight.
Too much of a good thing
Around 7,000 people in the UK live with Huntington’s disease. This disease occurs when certain nerve cells in the brain, especially in an area called the basal ganglia (involved in movement fine tuning), gradually stop working. This leads to jerky, involuntary movements called chorea, along with changes in mood, memory, and concentration.
The cause lies in a single gene — the huntingtin gene. Normally, this gene makes a protein that helps normal nerve cell functioning. But in Huntington’s disease, a small section of the gene’s code, called CAG, is repeated too many times. This creates a faulty huntingtin protein, which damages the nerve cells that it was supposed to protect. This change in the code can then be passed on to a person’s children, meaning that if a person has Huntington’s disease, there is a 50% chance that their child will inherit it too.
Until recently, treatment has been limited to symptom management. As techniques for gene therapy developed, hope for a treatment began to rise. Now that hope has become a reality.
Enemy turned friend
The hope comes in the form of a harmless virus that delivers healthy genetic code directly to the part of the brain most affected— the basal ganglia. This code is known as mRNA, and it instructs the body’s protein factory to make the correct version of the huntingtin protein. This healthy protein can then outcompete the toxic one, slowing down the damage to nerve cells that it would otherwise wreak.
This gene therapy is known as AMT-130 and was developed by scientists at uniQure, a gene therapy company based in Amsterdam. During the early clinical trial, they found that this treatment slowed down the progression of Huntington’s disease by an incredible 75% over three years. Significantly, they also found that neurofilament light protein, a marker for nerve cell damage found in the fluid within your spine, was lowered by 8.2% below baseline after 36 months of the treatment. This serves as evidence that the treatment is stopping the killing of the patient’s nerve cells. This could mean years of independence and quality of life returned to patients and their families.
What next?
The treatment still needs to pass all the necessary checks. For example, this includes researchers in the field reviewing their work and regulators like the FDA providing approval for this to be marketed to patients. UniQure has stated that they will submit an application to US regulators early next year, and given the exceptional circumstances, we might expect approval as soon as later that same year. If previous gene therapy treatments are any indication, the cost of this treatment once approved could reach up to or exceed 1 million pounds per treatment.
These limitations should not take away from the breakthrough of this treatment: both for patients suffering from Huntington’s and for anyone suffering from a genetic disease.
Future of gene therapy
Huntington’s is not the first genetic disease to benefit from gene therapy— similar treatments have already changed lives for people with spinal muscular atrophy and certain inherited forms of blindness, to name a few. This is not the start of something new but rather further proof of the limitless possibilities that gene therapy provides. Breakthroughs in gene therapy techniques have been occurring consistently in the last decade or so, and with increasing speed.
What comes next? A treatment for cystic fibrosis, muscular dystrophy, or even the complete eradication of Huntington’s disease once and for all? No one can say for sure. But until then, gene therapy will continue to give the millions of people suffering from genetic diseases and their families something truly important: hope for a brighter tomorrow.
