One More Test to Wonder About?by Natalie Jacobs July 2, 2014
If you could find out with moderate medical certainty when you’re going to die, would you? It’s the kind of question you ask when you’re feeling philosophical but it might become an increasingly more important line of inquiry. Other thought questions that were once purely hypothetical – like, “what if you could know the sex of your baby before it’s born?” – have become realized in recent history. Advances in medical technologies keep this progression going faster and faster and the study of genetics is the new frontier. Sequencing, cataloging and analyzing DNA is an attempt to answer the big, as-yet-unanswerable questions, specifically those related to diseases, why we get them and if we can wipe them out.
“Genetics has become quite revolutionary in the pace at which we can do things,” Dr. Galasko, a professor in the Department of Neurosciences at UC San Diego, who researches genetic aspects of both Parkinson’s and Alzheimer’s diseases, says.
Ashkenazi Jews are no strangers to questions about genetics and the diseases they cause. From Tay-Sachs to Gaucher to Cystic Fibrosis, doctors have long been advising members of this Jewish population about the risks associated with their gene pool. Recently, genetic testing for the rest of the world has caught up. Doctors and scientists are isolating genes to understand the biological makeup of myriad diseases, and start-up companies like 23andMe are making gene sequencing as easy as an at-home pregnancy test. All of this contributes to a global database of genetic information from which researchers can work in the hopes of better understanding how the human body functions. In many cases, the genes of Ashkenazi Jews remain specifically interesting for these researchers. One such area is Parkinson’s disease.
“There are a number of different genes that have been identified for Parkinson’s over the last roughly 20 years,” Galasko, who is also the lead doctor on a genetics study sponsored by the Michael J. Fox Foundation, says.
“[The] LRRK2 [gene] was discovered in 2004 in a few families that had Parkinson’s disease. Because of the existence of large banks of DNA among different research groups, people were able within a year or two, to look at how common LRRK2 findings were across the world.”
They’ve isolated this gene as the most common genetic factor in Parkinson’s patients. The purpose of the Fox Foundation’s genetics study, called Parkinson’s Progression Marker Initiative (PPMI), is to continue identifying the biomarkers that are associated with Parkinson’s disease. It started out as a study to evaluate the progression of the disease but it recently evolved to focus on genetics because that is where they see the most potential for discovering something that will impact the onset and progression of the disease.
“The idea [for the study] is to identify people who are at risk of developing Parkinson’s because of particular genetic risk factors,” Galasko says.
Shortly after researchers determined that LRRK2 is the most significant gene in causing Parkinson’s disease, they discovered that in people with Ashkenazi Jewish backgrounds, it was an even stronger predictor. Ashkenazi Jewish people are more likely to carry the gene (30-60 out of 100) and of the five-10 percent of people who have genetic causes of Parkinson’s, 15-20 percent of them are Ashkenazi. Because of this, Dr. Galasko and the team at the Michael J. Fox Foundation are specifically looking for Ashkenazi Jews to participate in their genetic study.
“By identifying milestones within a very well characterized group of people who are LRRK2 carriers,” he continues, “we may be able to identify markers that we can then generalize to a lot of other people who may be at risk for Parkinson’s.”
Across the United States, the study is hoping to enroll 250 people with the LRRK2 gene who have Parkinson’s disease and 250 people who are carriers but do not have Parkinson’s. Their data will be added to the more than 600 people who are currently enrolled in the PPMI study on the non-genetic side of the equation. Ultimately, they will have a database of well-characterized genetic information that will be used to create new treatments and ultimately maybe cure the disease (though that is still a very distant goal).
“We stand at a point where treatment studies are being planned to try to delay onset of certain types of symptoms,” Galasko says, “or perhaps to slow progression, but we really need objective measurements to help us initiate these trials and measure their outcomes.”
Involvement in the study for those with LRRK2 requires clinical procedures like blood draws, detailed physical examinations, testing of cognition and smell, testing of movement, and brain imaging. There is also the option to get a spinal tap or lumbar puncture once fully approved for the study.
As with most genetic mutations, just because a person carries the gene doesn’t mean he or she will develop the disease. But, this is science and it only works through trial and error. Galasko says it’s about the possibility of catching symptoms early on and working toward a cure.
“Knowing how to build this very detailed roadmap using biomarkers provides us with all of the tools to develop treatment studies,” Galasko says.
You can find more information about the study by visiting michaeljfox.org/ppmi/genetics.