Mechanisms of aluminium neurotoxicity in oxidative stress-induced ...

INTRODUCTION
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PD, also called idiopathic PD or primary parkinsonism, is the most common
movement disorder besides essential tremor and the second most common age-related
neurodegenerative disease after Alzheimer's disease (AD) (Fahn and Przedborski 2000,
Tanner and Aston 2000, Mayeux 2003, Fahn and Sulzer 2004). Moreover, PD is the
main cause of chronic progressive Parkinsonism accounting for ~80% of cases.
Parkinsonism, also known as Parkinson‟s syndrome, atypical Parkinson‟s or secondary
Parkinson‟s, is a term which refers to the neurological syndrome characterised by three
cardinal motor symptoms: bradykinesia, rigidity and tremor.
Prevalence and incidence of PD
More than 4.5 million people worldwide were affected by PD in 2007. Due to
increasing life expectancy of the general population and multiplication of effective
therapies, the number of individuals over 50 years of age with PD was expected to
double to around 9 million patients in the world‟s 10 most populous nations between
2007 and the year 2030 (Dorsey et al. 2007). At the time of writing, PD is affecting
approximately 6 million people worldwide.
In regards to disease epidemiology, the mean age onset of sporadic PD (also
known as idiopathic PD) is 55 years, but is now thought to be in the early-to-mid 60s
(Inzelberg et al. 2002). Early onset of PD (EOPD) is rare, about 4% of patients develop
clinical signs of the disease before 50 years (Van Den Eeden et al. 2003). Within
EOPD, there appear to be two groups namely: young-onset PD (YOPD), with onset
between 21 and 40 years, and juvenile Parkinsonism (JP), with onset at