Abstract
Parkinson's disease is the second most common neurodegenerative disorder and affects 2% of the population over the age of 60 years. Due to the increasing proportion of elderly individuals in developed countries, Parkinson's disease and related neurodegenerative disorders represent a growing burden on the health care system. In the majority of cases, the cause of the disease is still unknown, and its elucidation remains one of the major challenges of the neurosciences. Recent findings in rare genetic forms of Parkinson's disease have allowed the development of novel animal models, providing a basis for a better understanding of the molecular pathogenesis of the disease, setting the stage for the development of novel treatment strategies. Several novel genes for monogenic forms of Parkinson's disease, such as PINK-1 for an autosomal-recessive early-onset variant, and LRRK2 for a relatively common late-onset autosomal-dominant form have recently been discovered, and several novel animal models have been generated on the basis of genes that had been found earlier. The combination of genetic, pathologic and molecular findings provide increasing evidence that the pathways identified through the cloning of different disease genes are interacting on different levels and share several major pathogenic mechanisms.