This is the first time we've studied animal models and clinical samples, and used them to look at RNA expression patterns of biomarkers in PD. Our other goal is to use this approach to identify subtypes of the disease so that treatment can be targeted more accurately and in addition, incorporated with clinical trials that facilitate the ability to identify new therapeutic and disease modifying agents.
April 14, 2015
Novel Blood Signature Analysis May Enable Earlier Parkinson’s Diagnosis… and Treatment.
In recent weeks, we’ve heard promising news on several fronts in the battle against Parkinson’s disease.
Two weeks ago, we learned about apparent progress in the development of an anti-PD vaccine. Then last week, we heard that researchers had developed a novel process they felt could enable doctors to diagnose PD much sooner by evaluating the way people typed on a keyboard.
It’s now axiomatic that the timing of diagnosis is paramount in the treatment of this disease. PD is often not diagnosed for ten years after the damage begins. Estimates suggest that up to 80% of the dopamine-producing neurons are already destroyed by the time someone receives a proper diagnosis of PD. For treatment to be truly meaningful, diagnoses must come much sooner than they do now.
A Novel Blood Signature Analysis
Now, in a study published in the journal Movement Disorders, we learn that PD might be identified earlier using a new blood signature analysis. This new research was conducted by the Mount Sinai Medical Center and – like so many others --- funded by the Michael J. Fox Foundation for Parkinson's Research.
The Mount Sinai team used a new approach to search for biomarkers – or at least “blood signatures” -- in the blood of PD patients who carry a known genetic risk factor for the disease, and in the blood of PD patients who do not.
At this point in the effort to ID the disease sooner, there’s only one blood feature that might signal an increased likelihood of developing PD: the presence of a mutation in a gene identified as leucine-rich repeat kinase 2, or LRRK2. (The mutation doesn’t carry a PD sentence; only some people with the mutation get the disease.)
Still, it’s a start. Less than two percent of all people with PD actually carry the LRRK2 mutation. It would be a big leap forward if science could find another similar bio-marker.
How the Study Worked
Using a "digital gene expression platform" to quantify 175 messenger RNA markers, the team sought to identify the molecular signature in the blood of Ashkenazi Jewish PD patients, including LRRK2 mutation carriers. Ashkenazi Jews are much more likely to carry the LRRK2 mutation – which may or may not lead to PD – than others.
They also made a similar examination of the blood of asymptomatic Ashkenazi Jews.
In addition, researchers evaluated the blood of four groups of mice with RNA (genetic material) that the study team predicted might form part of a PD signature.
While the approach might seem a bit challenging to grasp (the link to the study abstract follows this post), the researchers could identify “RNA signatures” in samples that correlate with the disease-causing mutations in the LRRK2 gene in PD patients. Most PD patients don’t carry the mutated gene, but the Mount Sinai scientists suspected that related pathways also play a role in much more common, non-inherited cases of PD. The key was identifying those “related pathways.”
Identifying PD “Subtypes”
Study lead author Dr. Stuart Sealfon, Chairman and Glickenhaus Professor in the Mount Sinai Health System Department of Neurology, said:
While excited about their findings, Sealfon -- like most other researchers before him -- saw the need for additional research: “The next step is to replicate this approach in a larger sample, where we track patients longitudinally and see how profiles are changing over time."
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Here’s the official study abstract: