Magnetic resonance image (MRI) of Parkinson's Disease, a degenerative disorder of the central nervous system. REUTERS/Neil Hall
The good news about Parkinson’s is that a scientist in Jerusalem has developed a test that detects the degenerative brain disease both definitively and earlier, hopefully improving the prognosis for patients.
The bad news is that the Mayo Clinic has noticed an association between Parkinson’s and melanoma, a deadly form of skin cancer. They can’t explain it, but a significant association has been found.
Parkinson’s disease is the second most prevalent degenerative brain disorder in the elderly, after Alzheimer’s. But by the time one knows one has the condition, it may be spiraling out of control.
By the time patients are symptomatic, around two-thirds of the brain cells that make dopamine (the substantia nigra part of the brain) are already dead, says Suaad Abd-Elhadi of Hebrew University of Jerusalem, winner of the Kaye Innovation Award for inventing the method to – finally – achieve categorical diagnosis of Parkinson’s. Not only that, but at an early stage of the disease.
Earlier diagnosis means identifying Parkinson’s before the dopamine cells die off en masse and symptoms appear (motor or cognitive or both). True, PD remains incurable. Even so, “Earlier diagnosis can help by seeing how a given drug affects the progress of the disease, for example,” says Abd-Elhadi.
A big problem is that early PD looks just like other neurodegenerative diseases, which hinders appropriate care, she explains. A great deal of effort is presently being put into delaying the progress of PD, for which purpose, one needs to know that one has it.
Using the kit invented by Abd-Elhadi, now one can know it, even before becoming asymptomatic. Which begs the question of under what circumstances one would check if one isn’t showing symptoms.
“PD isn’t as common as cancer, for instance,” she says. “But there is a not-small percentage of people who have PD in the family, and if one has it in the family, it pays to go get checked.”
But how to know definitively that one has PD, not Alzheimer’s for instance, or some other disease of the nervous system? The definitive test Abd-Elhadi developed is based on the fact that PD is associated with a weird protein called alpha-synuclin.
According to recently-published research, the pathological form of alpha-synuclin appears first in peripheral nerves, usually in the digestive system, and only appears in the brain at later stages of Parkinson’s, says Abd-Elhadi. “It’s known that patients with early-stage PD have problems with their digestive systems, even with swallowing,” she says. “Only later in the disease does the pathology reach the brain.”
Alpha-synuclin binds to fat molecules, called lipids, on cell membranes, Abd-Elhadi explains. What she did is identify the lipid types, originating in both peripheral tissues and brain cells, to which alpha-synuclin binds best.
Using these lipids, she invented a minimally invasive, highly sensitive kit to test for Parkinson’s, called “lipid ELISA” (ELISA stands for “enzyme-linked immunosorbent assay.”) She achieved proof of concept – that the invention works in people with different stages of PD, and people without the disease.
Obviously this isn’t a home kit for the perennially perturbed. This is an invention for hospitals, or possibly for groups of workers exposed to industries that are high-risk for PD, such as agriculture. Pesticides have an unfortunate association with the development of the disease, Abd-Elhadi points out.
As for the melanoma association, causality remains a mystery. But the Mayo Clinic found that melanoma patients had a fourfold higher risk of developing Parkinson’s, and people with Parkinson’s had a fourfold higher risk of having preexisting melanoma (which means they had it in their medical history).
“There appears to be an association between melanoma and PD,” the Mayo clinicians wrote cautiously in a paper by author Lauren Dalvin and the team. Their conclusion: Doctors should warn their melanoma and Parkinson’s patients to keep an eye out for the other disease.