Parkinson’s Disease is caused by… no one seems to know conclusively.
After the question – ‘What is Parkinson’s?’ which I wrote about earlier this week (link), ‘What is the cause?’ is one of the questions I am most often asked, and clearly, as an accountant with absolutely no science pedigree, I have absolutely no idea. As a result, I have tried to dig into it a little. After all, logic and common sense dictate to me that there is a much higher chance of curing something if you know what causes it.
The simple answer is it appears no one knows what external factor or factors trigger it. Like all things, there are threads of facts, and many people have their own theories (of which I can’t judge), but the scientific consensus seems to be that:
On a personal level, just to get it out of the way, my onset was unusual and so absolutely far from clear in its suddenness of onset that there was actually an article in the Lancet written about it (link). It is many a parent’s dream to see their child have an article published in such an illustrious journal – sadly for me it was as a patient. So my question is more general.
Genetics
A certain percentage of patients have a hereditary cause – i.e., it is genetic. People differ on the percentages. Many articles state 10-15%, Professor Bas Bloem – a very articulate and prominent expert in the field – seems to suggest in this paper that it is higher but with an important clarification. He identifies two types of Parkinson’s, broadly:
- Monogenic Parkinson’s Disease: This is caused by specific, identifiable genes. If you have one of these genes, you have a high chance of developing Parkinson’s disease. It’s a direct genetic cause. These cases seem to count towards 3-5% of PD cases.
- Non-Monogenic Parkinson’s Disease: This involves multiple genetic variations that each contribute a small amount to the overall risk. These variations together can explain a significant portion of the risk, but they don’t guarantee that someone will develop Parkinson’s disease. It’s more about having a higher likelihood due to a combination of many small genetic factors. These cases seem to count towards 16-36% of PD cases.
So, assuming a minority of the cause of PD is genetic, what about the rest? This is where there is even more fierce debate. Professor Bloem’s view shared in an interview with the David Phinney foundation (and he very eloquently talked about it on a recent, and highly recommended, Movers & Shakers podcast) suggests that environmental toxins, particularly pesticides, play a significant role. He states that Paraquat, a highly toxic weed killer that has been banned in more than 60 countries but is still used in the US, is very toxic to the area of the brain that Parkinson’s impacts, the substantia nigra. Pesticide use began worldwide in the 1950s to feed a rapidly growing world population. People can be exposed to pesticides through well water and the food chain.
There are many other ideas out there – some are probably more and some less well-researched and fact-checked. There are many who state a link between Gut-Brain, Nose-Brain, and a combination of these and many more.
What Does This Mean for All of Us?
Firstly, it is clearly important that science works this out. Parkinson’s is, in most estimates, on the rise. If environmental factors are causing it, it would make sense to solve the issue of the source pesticides and toxins, and then this disease can recede.
Secondly, once a cause is identified, it would seem far easier to direct effort to both the cure and treatment, and billions of dollars of research can be zeroed in on a focused basis.
Thirdly, if it is genetic, then it is both a risk factor for future generations and an opportunity to intensify efforts to solve the challenge for future generations or at least target genetic-based specific solutions to them.
But practically, for the current PD patient, it means very little.
As my late neurologist told me after a few weeks and after the article was written, my onset is indeed very strange and atypical and could be debated and studied for years. But bottom line – you have had 2 DaTscans both with the same result, you clinically have the clear symptoms, and you respond well to the treatment, so it has to be treated as PD. Forget how it happened – get on with exercise, yoga, mindfulness, good diet, doing fun things, and treating it with meds… it is what it is, now fight like hell.
In Summary:
To me, it doesn’t make a whole lot of difference how it came to be, other than some relief that it appears not to be genetic. Once diagnosed, I think the job is to lean into all the mechanisms I and others speak about in the daily plod of life. For science, however, this is a critical question as it determines the path to a cure or better treatment – I hope they nail it soon – for me and for others.
Please note – this is my personal blog and it is written from just my personal bias ignorant view – it is not a medical source so no one should rely on it. It is clearly written for a non scientific audience including me.
