What causes Parkinson’s?

Parkinson’s is a neurodegenerative condition which affects the brain’s ability to produce dopamine – the chemical which helps us control movement – but it’s not clear what causes this. Active research into the causes of Parkinson’s continues every day.

While we don’t know why some people develop Parkinson’s but not others, research suggests that a combination of genetic and environmental factors may be responsible:

Genetic causes

It is rare for Parkinson’s to be passed from parent to child. However, in recent years a number of cases have been identified in which Parkinson’s seems to be at least partly genetic. In these cases, a mutated gene appears to have passed from one generation to the next, and Parkinson’s has developed in several people in the same family. But the chances of this happening are still very low.

Scientists believe certain genes may play a role in the genetic causes of Parkinson’s – this is an important focus for research, as we try to understand how these genes affect the underlying risk, onset (start), and progression of Parkinson’s. Discoveries in this area could be important for future treatments.

Environmental causes

Some evidence suggests that environmental factors, including toxic chemicals, viruses, bacteria, and heavy metals, may cause dopamine-producing neurons to die, leading to the development of Parkinson’s.

In particular, there has been much speculation about a link between the use of herbicides and pesticides and the development of Parkinson’s.

In the early 1980s, a small number of drug users in California mistakenly took heroin that had been contaminated with a dangerous synthetic drug called MPTP. Anyone who took the contaminated heroin developed very severe and irreversible Parkinson’s-type symptoms almost immediately.

This unfortunate incident has led to significant scientific advances. MPTP has since been used widely in basic research and has helped scientists to learn much more about Parkinson’s.

Combined causes

Scientists currently believe that, in most cases, both genetic and environmental factors interact to cause Parkinson’s. The extent to which each factor is involved varies from person to person. Unfortunately, with both genetic and environmental factors, it’s very hard to prove exactly what caused a person to develop Parkinson’s.

Risk factors

The single biggest risk factor for Parkinson’s is age, as most people are over 60 when they develop the condition. However, 12-15% of people with Parkinson’s are under 45, which is referred to as Young Onset Parkinson’s Disease (or YOPD).