Is Parkinson’s Real?

Genetic research suggests it may be three different conditions

Last year I chaired a debate in which an American neurologist suggested that Parkinson’s did not exist - or at least described such a broad range of symptoms that it was not useful as a definition of one disease. At the time I thought this was just a piece of provocation from a panellist determined to be noticed. But this week I heard about some intriguing research that what we call Parkinson’s may be at least three very different conditions.

The research comes from a drug discovery company called C4X Discovery and its CEO Clive Dix , once head of research at Glaxo, told me it could have huge implications:

“I've been in drug discovery since 1979 and this is probably the most exciting thing I've seen that really is close to affecting how we treat people.”

C4X’s work, he explained, involves applying sophisticated mathematical techniques to try to identify new targets for potential drugs by examining variations in the genetic code for thousands of people. “Most diseases have some form of genetic background to them - it may not be a single gene, but that you have a predisposition to a certain disease based on your genetics.”

But their work on the genetic code of people with Parkinson’s turned up a surprising result - there were three distinct subgroups among the people diagnosed with the disease: “They were very, very distinct, says Clive Dix. “They weren't even overlapping, which gave us a sort of footprint or a barcode for each of the groups.” His conclusion - this is confirmation of what many neurologists believe: “They don't know what Parkinson's is, but it's not a single disease.”

You might think this was depressing news - if neurologists don’t really understand what Parkinson’s is what hope is there of finding a cure? Yet there is already evidence that the C4X findings could lead to better targeted treatment. The company provided the genetic signatures of the three sub-groups to Australia’s Garvan Institute of Medical Research, which used the information in an examination of a failed drug trial.

The Institute divided the patients on the phase three trial into the different groups; “What they found, “ explains Dix, “ was that in one of the groups all the patients responded to the drug and responded very, very well.”

This finding should have major implications for the design of drug trials. Researchers will want to use genetic tools when recruiting patients for trials and then try to zero in on the groups which respond best to a drug.

“This is an important milestone in bringing precision medicine to patients,” says Dr Richard Wyse from Cure Parkinson’s, the charity which was instrumental in bringing C4X and the Garvan Institute together.

What this brings home to me is that genetics will now play a key role in the treatment of Parkinson’s. Four years after I was diagnosed, I’ve only just had my first genetic test. Surely that should be as routine as a DAT-scan the moment a neurologist decides that you show signs of having that mysterious condition called Parkinson’s?