Huntington's disease: northern Scotland has one of the world's highest rates and rising sharply - here's why

Huntington’s disease (HD) is a devastating inherited neurodegenerative condition that causes a slow but relentless decline in mental health, thinking processes, speech, swallowing and balance, resulting in uncontrollable jerky movements.

Those who have the condition will eventually lose the ability to walk, talk, eat, drink, make decisions or care for themselves. A fatal condition, it typically takes between 15 and 25 years from a person developing symptoms until they die. These symptoms generally begin between the ages of 30 and 60 but can appear before or after this range.