WPC Science Day Two: Genetics Updates

From James Beck, Ph.D., Director of Research Programs

Here are some additional scientific updates from this week's 2nd World Parkinson Congress (WPC).

Michael Schlossmacher, M.D., reported the results of his recent experiments that demonstrate that mutations in the GBA gene, which were recently identified as a major risk factor for Parkinson's disease (PD), actually contribute to an increase in the levels of alpha-synuclein in nerve cells. Alpha-synuclein is the protein that accumulates in dying nerve cells and is the hallmark of Parkinson’s disease. This result provides a biological explanation as to the significance of these GBA mutations and their relevance to PD. That is to say, Dr. Schlossmacher has shown how mutations in the GBA gene are related to an increased risk of PD. His work has gone through peer review and is currently awaiting publication—we will let you know when it is published and report on his findings in more detail.

Additionally, Haydeh Payami, Ph.D., a research scientist from the Wadsworth Center and Director of the NeuroGenetics Research Consortium in New York State, reported late-breaking results of the re-analysis of a large-scale genetics study her team published this past March in Nature Genetics. The re-analysis examined whether there was a genetic interaction with the onset of Parkinson’s disease and the amount of coffee study participants consumed. Her team found a strong link with a particular gene called GRIN2A, which makes one component of the receptor protein that binds to an important neurotransmitter called glutamate. When this receptor protein binds too much glutamate, it becomes over-activated and can lead to cell death.

What is the role of coffee? Well, the caffeine in coffee indirectly alters how much glutamate is released from neurons by blocking the function of another receptor protein—the adenosine A2A receptor. This in turn, may prevent the cell death observed in the presence of too much glutamate. Indeed, epidemiological evidence suggests that coffee drinkers may have a lower risk of PD. However, Dr. Payami introduced a wrinkle in this concept. She suggests that her teams’s genetic data reveals that only some people may benefit from the strategy of blocking the A2A receptor. You see GRIN2A comes in two forms and only 25 percent of the population have the version which Dr. Payami suggests is beneficial.

Please keep in mind that Dr. Payami's study results were part of a late-breaking science presentation at the WPC, meaning the results were fresh from the lab and will need to be validated and reviewed by her peers. So as compelling as the results are, it will be interesting to see if these findings will stand after a critical examination has been performed. Whether her hypothesis regarding which form of GRIN2A is important is right or wrong, she raised an a critical issue that may be impact future drug discovery—the significance of genetically characterizing research participants. We are all genetically different, so is it so surprising that some people respond better to certain drugs than others? Maybe this is why many drugs fail clinical trials? What do you think?

As the science advances, you can count on PDF to keep you updated.