What is Huntington's disease? In major breakthrough, experimental gene therapy slows down progression by 75%

Huntington’s disease is a hereditary condition that leads to the progressive degeneration of nerve cells (neurons) in specific areas of the brain. It mainly affects regions that control voluntary movements and other key brain functions. Over time, individuals with HD experience motor, emotional, cognitive and behavioural challenges. Doctors say it has been successfully treated for the first time through experimental gene therapy, with patients showing an average 75% reduction in disease progression.

For instance, involuntary movements may occur in the fingers, feet, face, or torso, which are characteristic of chorea. These movements often become stronger when the person feels anxious or distracted. As Huntington’s Disease advances, these movements tend to become more severe and noticeable.

For some individuals, chorea, a condition causing involuntary, jerky movements, can make walking difficult, increasing the risk of falls. However, not everyone with Huntington’s Disease (HD) develops chorea. Some may experience rigidity, characterised by stiffness and reduced movement, a condition known as akinesia.

In some cases, people initially show chorea but gradually become rigid as the disease advances. Additionally, some may develop dystonia, where they hold unusual, fixed body postures. Akinesia and dystonia can sometimes overlap or alternate. Other movement issues can include tremors, unintentional shaking of muscles and irregular eye movements, which can appear early in the disease.

Physical symptoms in Huntington's disease

Physical symptoms can involve slurred speech and difficulties with swallowing, eating, and walking. Due to these challenges, many individuals with HD may experience weight loss caused by trouble feeding, choking and frequent chest infections. Other common symptoms include insomnia (difficulty sleeping), low energy, fatigue, and seizures. As the disease progresses, the person may become confined to a bed or wheelchair.

'75% slowing of clinical progression'

The trial results, involving 29 patients, were announced in a statement by the company uniQure, though the full findings have not yet been published for peer review by independent experts. According to the data, three years after undergoing surgery, patients showed an average 75% reduction in disease progression, based on a combined measure of cognitive abilities, motor skills, and daily functioning, as per a BBC report.

According to Prof. Sarah Tabrizi, this means that the deterioration typically seen over one year would now take around four years, potentially offering patients many more years of high-quality life. The breakthrough treatment involves a form of gene therapy delivered through a delicate brain surgery lasting between 12 and 18 hours, the report said.

"We never in our wildest dreams would have expected a 75% slowing of clinical progression," BBC quoted Tabrizi as saying.

The chief medical officer at uniQure, Dr Walid Abi-Saab, stated he was "incredibly excited" about what the outcomes mean for families and mentioned that the treatment had "the potential to fundamentally transform" Huntington's disease.