Parkinson’s Disease Is
Not Inevitable may influence when and how people get
Parkinson’s disease. Genetics Could One Day
Dictate Your Treatment
Most genetic mutations associated with
Parkinson’s disease raise one’s risk a
small amount. Even people with higher-
risk mutations will not definitely get
PD. In other words, no known mutation
carries a 100 percent chance of causing
Parkinson’s. Researchers are studying
people with mutations linked to PD but
who do not exhibit symptoms to uncover
protective factors (genetic or otherwise),
which could lead to treatments to
prevent Parkinson’s. Genetics and Environment
Can Interact to Cause
Parkinson’s Science is moving away from a “one-size-
fits-all” treatment approach for disease.
Your genetics may soon tell doctors what
therapy is best for you. Clinical trials are
already under way to assess whether new
therapies may benefit people with genetic
mutations linked to PD. Ultimately,
tailoring a treatment regimen to one’s
individual biology — precision medicine
— brings greater likelihood of success.
Certain PD Mutations
Are More Common in
Some Groups
Some genetic mutations are more
common in certain familial and ethnic
groups. For example, these three
mutations are of great research interest:
+ + SNCA: very rare mutation found in
families with many PD diagnoses
+ + LRRK2: more common in people of
Ashkenazi Jewish, Basque or North
African Berber descent
+ + GBA: fairly common in people of
Ashkenazi Jewish descent
While people of other descents can
carry these mutations, researchers often
recruit for genetic studies from these
populations because there is a greater
likelihood of finding mutation carriers.
Mutations May Impact
One’s Type of Disease
No one with Parkinson’s has the same
disease experience. Even people with the
same genetic mutation experience PD
differently — such as being diagnosed
at different ages. There are some trends,
though. People with a rare type of GBA
mutation, for example, are more likely to
develop cognitive impairment. Scientists
are studying these known genetic
connections and looking for other genes
or biological or lifestyle factors that
While some cases of PD may be
attributed more heavily to genetic
mutations (SNCA, for example), for
many, an environmental factor (or
combination of factors) tips the scale.
An old saying is that “genetics loads the
gun and environment pulls the trigger.”
For example, pesticide exposure can
contribute to the risk of developing
PD. Some studies have found those
who do develop PD after contact with
pesticides have genetic mutations that
affect the way the body metabolizes
these toxins. It’s that combination of
genetic susceptibility and environmental
exposure that influences disease risk. It is
possible, too, that environmental factors,
such as eating a healthy diet, could play a
protective role.
Bringing therapies from the laboratory to
the pharmacy requires the participation
of thousands of volunteers in clinical
trials. Look at how far we’ve come in
Parkinson’s genetics research in a short
time, and imagine where we’ll be in
another 20 years with your help.
Genetic Mutations Teach
Us about Disease
Within the body’s cells, the role of genes
is to direct the production of proteins —
worker molecules that are responsible for
many aspects of life, including what we
look like and how our bodies function.
Genetic mutations can change how much
protein is made or how proteins work.
This can ultimately lead to disease, such
as Parkinson’s. Studying how changes in
genes and proteins lead to disease allows
researchers to get a better understanding
of how PD develops and how we can
hopefully stop it from progressing or even
beginning in the first place. For example,
mutations in a gene called LRRK2 are
believed to increase activity of the
LRRK2 protein, which is not good for our
brain or other cells, and can result in PD.
Scientists are developing medications,
called LRRK2 inhibitors, to block these
LRRK2 proteins and keep cells healthy.
Chapter 3 — Genetics and Parkinson’s Research
31