Genetics of parkinsonism

Area of Science:

• Neurogenetics
• Molecular Neurology

Background:

• Genetic mutations, particularly in alpha-synuclein, were the first identified causes of Parkinson's disease (PD).
• Subsequent research identified additional highly-penetrant (Mendelian) mutations in genes such as parkin, DJ-1, PINK1, LRRK2, and ATP13A2, revealing significant etiological heterogeneity.
• Emerging evidence highlights the role of low-penetrance mutations (e.g., LRRK2 Gly2019Ser) and polymorphic variants in alpha-synuclein and LRRK2 as significant genetic contributors to sporadic PD.

Purpose of the Study:

• To review the genetic landscape of Parkinson's disease, encompassing both familial and sporadic forms.
• To highlight the discovery of key genes associated with PD etiology over the past decade.
• To emphasize the ongoing challenges in fully elucidating the genetic architecture of common PD forms.

Main Methods:

• Review of linkage mapping and positional cloning studies.
• Analysis of genetic mutation data from Parkinson's disease cohorts.
• Examination of population-based genetic association studies.

Main Results:

• Identification of alpha-synuclein, parkin, DJ-1, PINK1, LRRK2, and ATP13A2 as major genes associated with Mendelian forms of PD.
• Discovery of the LRRK2 Gly2019Ser mutation and variants in alpha-synuclein and LRRK2 as relevant genetic factors in sporadic PD.
• Demonstration of significant genetic heterogeneity in the etiology of Parkinson's disease.

Conclusions:

• The genetic basis of Parkinson's disease is complex and heterogeneous, involving multiple genes with varying penetrance.
• While significant progress has been made in identifying PD-related genes, understanding the genetic determinants of sporadic PD remains a primary challenge.
• Future research should focus on resolving the complete genetic architecture of common Parkinson's disease forms.