Overview of the genetics of parkinsonism

During the last century, a large number of environmental factors were proposed as risk factors for the development of Parkinson’s disease (PD). Nevertheless, most epidemiological studies have been inconclusive, and the etiology of PD has remained largely unknown (Lees et al. 2009). Second to increasing age, a family history of PD is the strongest risk factor for the development of disease (Sellbach et al. 2006). PD is clinically defined as a syndrome with variable combinations of bradykinesia, rigidity, tremor, and postural instability (Lees et al. 2009). Pathologically, PD has traditionally been characterized as a disease with degeneration of dopaminergic neurons of the substantia nigra combined with the presence of Lewy bodies and cytoplasmic eosinophilic inclusions in surviving dopaminergic neurons and in other parts of the brain (Dickson et al. 2009).