Doctors have successfully treated Huntington's disease for the first time, with a new gene therapy slowing the disease's progression by 75% in patients. The treatment, which involves delicate brain surgery, has given patients decades of 'good quality life' and has the potential to prevent symptoms from emerging if administered early. The disease, which is fatal and has no cure, affects approximately 75,000 people in the UK, US, and Europe. The treatment is expected to be expensive, but it offers hope for those affected by the disease.