Parkinson’s disease affects nearly 1 million Americans and is the most common disorder that affects movement. I have worked on Parkinson’s for over 20 years and although there are treatments that reduce the motor symptoms, at least initially, Parkinson’s has a huge impact on the quality of life of patients and their loved ones. It’s one of the major uncured diseases of the 21stSt century and we desperately need therapies that slow, halt or even prevent the disease. This is why it’s critical to be aware of the early signs of this disease. Read on to find out more—and to ensure your health and the health of others, don’t miss these Sure Signs You’ve Already Had COVID.
Parkinson’s is a common progressive movement disorder that affects people later in life, typically in their 60s. The disease is mainly defined as a collection of motor symptoms, such as tremor, slowness of movement, and muscular rigidity. However, there is a prodromal phase prior to the onset of motor symptoms where one can develop different non-motor symptoms such as constipation, loss of sense of smell or REM sleep behavior disorder. Later in Parkinson’s after the onset of motor symptoms, patients can develop additional non-motor symptoms such as anxiety, depression, pain or dementia, as the disease pathology spreads throughout the brain.
Age is the greatest risk factor for Parkinson’s, yet genetics and environmental exposure also combine to play major roles. Inherited cases (familial) often occur earlier in life, typically below the age of 50, but can also occur later with certain genetic mutations such as in LRRK2. A large number of common genetic variants have been identified that are associated with very small amounts of risk for Parkinson’s, whereas exposure to certain pesticides, infections, and occupational exposure are also associated with Parkinson’s risk. The disease is more prevalent in males than females.
Typically, someone with Parkinson’s would initially present with motor symptoms such as tremor, slowness of movement, rigidity or gait issues (shuffling, short steps) often appearing first in an arm or leg on one side of the body. Other symptoms may include a mask-like face, vocal issues, reduced arm swing, stooped posture, slow reaction time, freezing movements, and frequent falls. Many years prior to motor symptoms, patients may have experienced constipation or loss of sense of smell, but these are not specific to Parkinson’s alone and therefore are not diagnostic criteria. A neurologist will attempt to rule out other common causes or diseases that produce similar motor symptoms prior to a diagnosis of Parkinson’s and will look to see if the symptoms get worse and progress with time (over the first few years) and respond to dopamine replacement therapy (the main symptomatic therapy for Parkinson’s patients).
If a patient develops motor symptoms they may also have a prior history of constipation, loss of sense of smell, or REM sleep behavior disorder (acting out ones dreams while asleep) as part of the prodromal phase of Parkinson’s. Later in life, patients may also develop anxiety, depression or dementia.
My research focuses on the underlying causes of Parkinson’s, particularly the contribution of genetics. About 10% of Parkinson’s cases are inherited and mutations in at least 15 different genes have been identified that cause distinct forms of the disease. We focus on understanding the normal role or function of these genes, or at least the proteins that they encode, and how these genetic mutations disrupt this normal function in brain cells using a variety of disease models. One type of brain cell that is affected or lost in Parkinson’s is called a dopaminergic neuron (a neuron that uses the neurotransmitter dopamine to relay signals in the brain and regulates the initiation of movement), and we particularly study the impact of genetic mutations on these neurons. We hope that an understanding of the genetic underpinnings of familial forms of Parkinson’s will provide critical insight into the more common sporadic form of the disease, and there is strong evidence to believe that these familial genes also play an important role in the sporadic disease. One example of this is the LRRK2 gene that is linked to familial and sporadic Parkinson’s, and is a major focus of our research. There is currently no cure or disease-modifying therapy for Parkinson’s but one is urgently required. We are working to identify novel therapeutic strategies and testing newly developed drugs to turn off or normalize the function of these genes. I have worked on Parkinson’s for over 20 years and the research field has made great progress that is now beginning to result in clinical trials of Parkinson’s patients that will test many of the genetic targets that we have been studying.
dr Darren Moore, Ph.D. is the Chair and Professor, Van Andel Institute Department of Neurodegenerative Science.