PINK1 and Parkinson disease: Genetically, mutations in synuclein α, P-TEN induced kinase 1 (PINK1), Leucine Rich Repeat Kinase 2 (LRRK2) and the E3 Ubiquitin Protein Ligase Parkin. Environmental factors such as frequent exposures to harmful chemicals such as pesticides or previous brain contusions in individuals also play a substantial role in developing PD (Bretaud et al., 2004).