Updates on the Genetics of Parkinson's Disease: Clinical Implications and Future Treatment.

Parkinson' disease (PD) is a common neurodegenerative disease with the pathological hallmark of alpha-synuclein aggregation within dopaminergic neurons. The etiology of PD comes from a complex interplay between genetic and environmental factors. Though most cases of PD are sporadic; a family history of PD is found in approximately 15% of patients. Pathogenic mutations are found in 5% to 10% of individuals with either familial or sporadic PD. In recent decades, because of the advent of next generation sequencing, more than 25 genes have been identified as causative genes in PD. These findings allow better understanding of the pathogenesis of PD, including aberrant alpha-synuclein homeostasis, defective mitochondrial functions, and impairment of the ubiquitin-proteasome and autophagy-lysosome pathways. Among the PD-causative genes, LRRK2 mutation is the most frequent mutation in autosomal dominant PD and Parkin mutation is prevalent in patients with autosomal recessive or early onset PD. Several genetic epidemiology studies in Asians have revealed a distinctive mutation spectrum from Western populations, reinforcing the importance of ethnic differences in PD. Proper genetic testing is recommended for patients with early onset, a strong family history, or associated red flag clinical features. Considering that clinical trials of disease-modifying therapy targeting patients with specific mutations are ongoing and we are in the era of precision medicine, this review highlights recent updates of genetic findings in patients with PD, focusing on Asian populations and practical recommendations for genetic testing. Keywords: Parkinson's disease, Genetics.