Ishimoto et al.’s (2018) study demonstrated the functional expression of OCTN1 in murine cultured microglial cells and suggested that OCTN1 expression negatively regulates the induction of inflammatory cytokine interleukin-1β. Moreover, clinical studies have shown that lower plasma levels of Ergo is associated with the incidence of several disorders including mild cognitive impairment (Cheah et al., 2016) and Parkinson’s disease (Hatano et al., 2014), suggesting the perception that a deficiency in Ergo may elevate the risk of disease. This evidence concerns the gene SLC22A4 and Parkinson disease.