Is losing the sense of smell a biomarker for Parkinson’s disease? Study will look for answer

NEW HAVEN >> Can you tell the difference between the scents of motor oil, pumpkin pie, rose and lemon?

If not, and if you're over 60 years old, you may be at risk of developing Parkinson's disease.

And you could be a candidate for a study sponsored by the Michael J. Fox Foundation seeking ways to detect the disease before symptoms develop.

Those are known as biomarkers, and whether losing the sense of smell is a biomarker is the purpose of the study, which is being conducted at 24 sites in Europe and Australia as well as the United States; the main site is the Institute for Neurodegenerative Disorders at 60 Temple St.

What Dr. David Russell, IND's clinical research director, and others are looking for is an "objective measure of presence of the disease and its progress to identify ... the disease very early, before you can see symptoms," Russell said.

There are medications to lessen the symptoms, which many people know from seeing Fox, star of "Back to the Future" and "Family Ties," in his TV appearances. He was diagnosed in 1991. Parkinson's is a neurological disorder that affects muscle movement because of a loss of dopamine in a specific area of the brain.

The search for a treatment, "preventing neurons from losing function or dying" is the "Holy Grail" of Parkinson's research, Russell said. So far, the search has been in vain.

"Parkinson's disease has been defined either as a collection of symptoms or by comparison to animal models of Parkinson's, which is flawed," Russell said. "In trying to get a neuro-protective treatment, it has failed many times."

What is known is that one in 100 persons over 60 will suffer from Parkinson's, according to michaeljfox.org (Fox's diagnosis, at about 30, was unusual). Loss of the sense of smell "is a common but little noticed symptom that may occur years before the onset of motor symptoms or a (Parkinson's) diagnosis," according to the website.

The new study is the second part of a $55 million biomarker study sponsored by the Fox Foundation. The first studied those who already had been diagnosed with the disease. Now, researchers want to study those who are at risk of developing Parkinson's. Besides loss of smell, other possible biomarkers being studied include a sleep disorder, REM behavior disorder, and a mutation in the LRRK2 gene.

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Is losing the sense of smell a biomarker for Parkinson’s disease? Study will look for answer