Based on this premise, we conducted a narrative review, searching in PubMed for relevant keywords, such as “genetic AND (Parkinson* OR PD)”, “mitochondria* AND (Parkinson* OR PD”), “toxic AND (Parkinson* OR PD)”, and by using more specific terms, such as “PINK1 AND (Parkinson* OR PD)”, “rotenone AND (Parkinson* OR PD)”, for each gene and toxic substance of interest. The gene discussed is PINK1; the disease is Parkinson disease.