Immune genes 'key in Parkinson's disease'

The immune system may have a key role in the development of Parkinson's disease, say US researchers.

In a 20-year study of 4,000 people, half with Parkinson's disease, the team found an association between genes controlling immunity and the condition. The results raise the possibility of new targets for drug development, Nature Genetics reports.

Parkinson's UK said the study strengthened the idea that immunity is an important driver of the disease. The team were not just looking for a genetic cause of the disease, but also considered clinical and environmental factors.

During their search, they discovered that groups of genes collectively known as HLA genes are associated with the condition. These genes are key for the immune system to differentiate between foreign invaders and the body's own tissues.

In theory, that enables the immune system to attack infectious organisms without turning on itself - but it is not always an infallible system. The genes vary considerably between individuals.

Some versions of the genes are associated with increased risk or protection against infectious disease, while others can induce autoimmune disorders in which the immune system attacks the body's own tissues.