I've been interested in the role of biomarkers for some time now and Debi Brooks recently posted to the thread on the New Year--New Look at Research
that significant progress is being made on the MJFF research front in this very crucial area:

Also, our significant work in biomarker discovery (and soon to be announced next-step biomarker verification) might result in more predictive measures -- an essential need for clinical design improvements and a boost for clinical practice as well.

From what I've gathered on establishing biomarkers, it's important not only in getting a more scientifically sound, accurate diagnosis, it also becomes an important player in validity of clinical trial outcomes and eventually in treatment. For background on the MJFF research initiative and the role of biomarkers in general see the MJFF Research Paper.

Given this news, a few (more) questions on biomarkers come to light.

Since there is currently no way to halt disease progression, it seems that the use of biomarkers would solely be limited to aiding in diagnosis at this point? I wonder, then, how this would pan out in the doctor's office when they are given tools or guidelines to more accurately diagnose (may be able to target people much earlier on) in the absence of a cure or any better treatment standard than what is available right now? In light of this, would you want to know that you most definitely had PD years earlier than your original diagnosis? I think there are serious psychological ramifications here and wonder how all this will play out. Maybe biomarkers will not be used until we have a disease modifying treatment in place?

I'm also curious as to what "weight" the biomarkers will have in diagnosis without the aid of technology like SPECT scans or analysis of cerebrospinal fluids? We definitely need this component if we are to accurately use biomarkers in diagnosis. Some of the more observational or clinical biomarkers that are being studied are the presence of REM sleep disorder and anosmia or decline in ability to smell. What if people present without these markers (just wondering because I would not be a match here)?

No real answers, but just figured it was worth examining whether we would really want to know at age 25 that we were most likely going to develop a neurodegenerative disease in the future? Would that have made a difference for you?

Just for fun, I've added a poll to see how many of us conform to some of the biomarkers being researched.

Laura