Addressing the question of nature vs. nurture, Dr. Sonia Mathur states that “Genetics loads the gun, environment pulls the trigger” (Mathur).
Parkinson’s Disease (PD) exhibits this pattern, with the vast majority of PD cases being idiopathic, likely the result of combined genetic and
environmental factors. While many researchers previously sought symptom-specific treatment, recent breakthroughs open the door for the
discovery of genetic and environmental causes so that disease prevention, and even reversal, emerge as viable possibilities. Recent research
demonstrates that certain types of PD are inevitable regardless of environmental factors, but most forms of the disease result from the ...view middle of the document...
While the effects are yet to be understood,
researchers have determined that most genetically induced Parkinson’s specifically destroys the substantia nigra through internal means, allowing
certain chemicals to accumulate in and exterminate the dopamine secreting neurons, ultimately causing PD (Golbe).
By contrast, other genes do not cause Parkinson’s directly but simply increase an individual’s susceptibility to environmental factors (Tanner). The
mutations of genes controlling the processing of chemicals associated with PD provide an example of this effect (Tanner, Strickland). When the
body fails to process and dispose of chemicals properly, the chemicals cause far more damage to the brain (Tanner). Additionally, these genes are
often ignored when researchers examine Parkinsonian patients, despite genetic implications in causing and propagating PD. While these internal
factors can cause PD independently, the beginning of the pathogenic deterioration often requires an external factor to initiate the process in order
for the disease to progress (Tanner).
Certain environmental factors can physically destroy the substantia nigra and trigger the expression of latent Parkinsonian mutations already
present in the genetic code (Tanner). In one of the most intriguing discoveries related to PD, a group of young people inadvertently provided a
central clue in determining the environmental causes of PD (Tanner). While using a recreational designer drug, the youths consumed “a street made
narcotic metabolite (MPTP)” (Strickland). This substance, which turned out to be remarkably similar to many common herbicides and pesticides,
proved highly destructive to dopamine receptors in the substantia nigra and caused acute Parkinsonian symptoms in the users (Strickland,Tanner).
Researchers subsequently studied the relationship between pesticide use and PD occurrence (Tanner) and discovered a direct correlation between
the use of the pesticides and the incidence of PD (Tanner, Strickland). In recent studies, researchers found that consumption of dairy, meat, and
agricultural products raised with high levels of pesticides increases the risk of PD. In addition to pesticides, heavy metals and chemical runoff from
paper mills were statistically related to higher incidences of PD (Strickland). Though chemical toxins often increase the occurrence of PD, traumatic
brain injury doubles the victim’s chances of acquiring PD (Lee). The high force impact initiates the destruction of dopamine producing neurons and
other factors finish the job (Lee). Phenotypical expression depends on the extent of environmental toxins and the genetic predisposition of
Despite recent advancements, research has been unsuccessful in discovering the exact etiologies of PD. Though researchers have gained a broad
understanding of both genetic and environmental factors which contribute to PD, the relationship between the two has eluded researchers for
nearly two centuries. Currently, the...