Parkinson\'s Disease Family and Cultural

Parkinson's Disease

FAMILY and CULTURAL STUDY of PARKINSON'S DISEASE

Brown, Rumsby, Capleton, Rushton and Levy (2006) state that Parkinson's disease (PD) is "...idiopathic disease of the nervous system characterized by progressive tremor, bradykinesia, rigidity, and postural instability." It is reported by Wood-Kaczmar, Gandhi and Wood (2006) that Parkinson's disease (PD) is a neurodegenerative disease that is both common and incurable. The majority of cases are sporadic and of unknown origin but several genes have been identified that, when mutated, give rise to rare, familial forms of the disease. The work of Hancock et al. (2008) states that Parkinson's disease (PD) is characterized by "...progressive depletion of dopaminergic neurons in the substantia nigra that manifests clinically as resting tremor, rigidity, and bradykinesia. Causal genetic variants in multiple genes (parkin, ?-synuclein, DJ-1, PINK1, and LRRK2) have been identified, but altogether, these rare genetic risk factors account for a small fraction of the overall prevalence of PD. The remaining majority of PD cases are likely due to genetic susceptibility variants, environmental influences, and complex gene-environment interactions."

II. Objective

The focus of this present study is to examine a specific population of individuals in regards to prevalence of this group in developing Parkinson's disease. This study has chosen to examine a population that has been exposed to farming chemicals and well water and who have developed this disease.

III. Literature Review

A. Environmental Factors

It was reported by Priyadarshi, Khuder, Schaub and Priyadarshi (2001) in the work entitled: "Environmental Risk Factors and Parkinson's disease: A Metaanlysis" that a study was conducted in order to examine the association between Parkinson's disease (PD) and exposure to environmental factors such as living in a rural area, well water use, farming, exposure to farm animals, or living on a farm, and pesticides. A series of metaanalyses of peer-reviewed studies were performed, using 16 studies for living in rural area, 18 studies for well water drinking, 11 studies for farming, and 14 studies for pesticides."

It is reported that the larger part of the studies reported consistently that risk of PD was elevated upon exposure to rural living and farming environmental factors. However, "Dose-response relationships could not be established due to the imprecise nature of the reported data. Our findings suggest that living in a rural area, drinking well water, farming, and exposure to pesticides may be a risk factor for developing PD." (Priyadarshi, Khuder, Schaub and Priyadarshi, 2001)

In a 2008 report entitled: "Pesticide Exposure and Risk of Parkinson's Disease: A Family-Based Case-Control Study" it is stated that "pesticides and correlated lifestyle factors (e.g. exposure to well-water and farming) are repeatedly reported risk factors for Parkinson's disease (PD) but few family-based studies have examined these relationships." (Hancock, et al., 2008)

In a separate study reported by Fleming, et al. (1994) entitled: 'Parkinson's Disease and Brain Levels of Organoclorine Pesticides" states as follows:

Epidemiological studies have suggested an etiologic relationship between pesticide exposure and Parkinson's disease (PD). Organochlorine pesticides were assayed in postmortem brain samples from 20 PD, 7 Alzheimer's disease (AD), and 14 nonneurological control cases. The three groups were similar in age at death, sex, and demographic variables. Only two of 16 pesticide residues screened were detected." (Fleming, et al., 1994)

However, there was a long-lasting residue of DDT found in the majority of Parkinson's disease cases. Additionally Dieldrin was detected "in 6 of 20 PD brains, 1 of 7 AD, and in none of the 14 control samples. Fleming et al. (1994) states: "Despite the relatively small number of brains assayed, the association between Dieldrin and the diagnosis of PD was highly significant (p = 0.03). Dieldrin, a lipid-soluble, long-lasting mitochondrial poison, should be investigated as a potential etiological agent of Parkinsonism." (Fleming et al., 1994)

B. Genetic Factors

While environmental factors are shown to increase the risk of developing Parkinson's disease there are also specific mutations linked to the development of PD in certain populations. For example it is reported that a study conducted on Parkinson's Disease and hereditary genetic risks of developing this disease states findings that researchers in the study "...found that ethnic Chinese individuals carrying a mutation they indentified in the LRRK2 gene are over two times more likely to develop the disease than non-carriers." (Mayo Clinic, Jacksonville, FL, 2004) the study was conducted at Mayo Clinic in 2004. The research team not only discovered the LRRK2 gene and the role it plays in Parkinson's disease but as well discovered "...a number of mutations in LRRK2 a gene that codes for poorly understood protein, leucine-rich repeat kinase." (Mayo Clinic, Jacksonville, FL, 2004)

One of the mutations 'G209S "has been shown to cause Parkinson's disease in people with and without a family history of the disease. G2019S is stated to be most common in "Berber Arabs and Ashkenazi Jews." (Mayo Clinic, Jacksonville, FL, 2004) it is however stated that this mutation is considered to be a risk instead of causative because there are individuals with this mutation who never develop Parkinson's disease. The frequency of LRRK2 G2385R is stated to be at 8% within ethnic Chinese patients. It is interesting to note that for some reason "this mutation does not appear to play a role in Parkinson's disease within other racial groups." The study reports: "Their analysis concluded that the G2385R mutation arose approximately 4,800 years ago, corresponding with the rise of Chinese civilization and the reign of Yellow Emperor Huang Di, credited with inventing traditional Chinese medicine." (2004)