Dr. Demetrius Maraganore did what most disease researchers do when they're searching for genetic links in a disease: he took it one gene at a time. But no matter what gene he looked at, his findings weren't that conclusive.
"If I told you your risk for Parkinson's disease was 4 percent instead of 2 percent, that wouldn't motivate you to change your behaviors very much," according to Maraganore.
He had found one gene that made a person about 2 percent more likely to get Parkinson's. Maraganore wondered, "why that gene?" If that gene mutates, why does that make a person more likely to get Parkinson's? This gene is actually a chemical that helps create neurological connections. Those make the brain function.
"That isn't a random process," he points out. "This wiring is very detailed. And as it turns out, there are chemicals that guide this wiring process during brain development."
The gene Maraganore found is part of a series of genes that make up what's called the axon guidance pathway, or the wiring pathway. Maraganore looked at the group collectively when there were multiple gene mutations or mistakes. Bingo.
"The findings were stunning. We found that common variations in axon guidance pathway genes -- or brain wiring genes -- resulted in a 90-times increase risk for Parkinson's disease," he says.
Maraganore says these results, statistically speaking, are conclusive, but he'll do further research on global populations.
Gene mutation is known for causing disease, but that doesn't mean Parkinson's is hereditary. Until now, researchers have looked at pesticide exposure, for example, as a possible environmental cause of the disease. But Maraganore says researchers should look at fetal development. He says brain wiring takes place in-utero. He wonders if maternal health factors might affect that wiring.
"If your mother was exposed to pesticides or not while she was pregnant with you, if your mother had an infection when you she was pregnant with you, if your mother smoked or drank coffee, how might those factors similarly alter the mapping of the brain and how might that also contribute to Parkinson's disease?" Maraganore says.
Maraganore says these findings may be useful in looking at other conditions like schizophrenia, Alzheimer's and dyslexia.
He says this finding ccould be used on middle- age men and women today. He's developing a clinical blood test that would determine whether a person is genetically predisposed to the disease, and to what severity.
"We're right there," he says. "The patents have been filed. We're in the process of doing the fine finishing to show that this is really a useful test for patients and clinics worldwide."
Maraganore says he is working with a team on a drug treatment for the disease if the genetic tests are positive. He says that treatment is about five years away.