For instance, the potential role of OCTs in the elimination of toxins whose chronic exposure is associated with several aging-related diseases such as Parkinson’s and cardiovascular disease, might suggest that the phenotype of Oct-deficient animals does not manifest just because the animals are not examined in the proper environment, or under the correct challenge or insult, or in the right moment of their life. The gene discussed is PLXNA2; the disease is Parkinson disease.