Parkinson's Disease Causes & Risk Factors

Conditions & Diseases: Brain & Nervous System

Parkinson's Disease

Causes & Risk Factors

Causes:

It is important to note that every human brain loses some dopamine producing neurons as a part of aging, but people suffering from PD lose about 80% or more of these neurons in the substantia nigra portion of the brain.

Dopamine is a chemical that transmits signals between substantia nigra and corpus striatum in the brain (These signals help muscles in making smooth and controlled movements). Degeneration of these dopamine-producing neurons causes Parkinson’s disease, but the exact cause of degeneration of these dopamine-producing neurons is not known.

Research studies state that a combination of genetic and environmental factors could lead to degeneration of dopamine producing neurons (9).

Genetic Factors:
Several genes are linked to PD such as mutation of the gene alpha-synuclein, triplication of the normal alpha-synuclein gene on one copy of chromosome 4, mutation of parkin, DJ-1, PINK1 and LRRK2. While mutation of Parkin, DJ-1 and PINK-1 genes causes early-onset forms of PD, in sporadic cases mutation of LRRK2 also causes PD. However, the research studies are still being done to understand as to how PD develops due to these mutations (8).

Environmental Factors:
Exposure to toxins such as 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, or MPTP (found in synthetic heroin), herbicides and pesticides could cause PD. No conclusive evidence is available to state that a particular environmental factor causes PD (8).

Medications:
Medications such as haloperidol (Haldol) and chlorpromazine (Thorazine) - (prescribed to treat psychiatric disorders), metoclopramide (Reglan, Metoclopramide HCL) – (prescribed to treat nausea) and valproate (Depakene) – (the epilepsy drug) when taken for long periods or in excess dosages may cause parkinsonian symptoms (9).

Risk Factors

Some of the risk factors identified are as follows:

Age: Advancing age is one of the risk factors. An individual is at higher risk of getting Parkinson’s disease, as she/he grows older.
Sex: Males are at a greater risk when compared to females.
Family History: Close relatives suffering from the disease could increase the risk of developing PD in a person (Genetic linkage).
Estrogen Levels: A woman is at risk of developing PD if she is not given hormone replacement therapy in post menopause or if she has undergone a hysterectomy.
Effect pesticides/herbicides: Agriculturists/farmers exposed to pesticides and herbicides containing toxins are at increased risk of developing PD, since some of the toxins inhibit dopamine production.
Traumatic Injury: A recent study showed many patients who suffered trauma head, neck, or upper cervical spine trauma are at risk for developing Post-traumatic Parkinsonism also called Post-traumatic Encephalopathy and also “Punch-Drunk Syndrome:"(10).

Article by Kona Vishnu, MS
Medical Writer,
OmniMedicalSearch.com