For example, reports have demonstrated that levels of inflammatory cytokines, such as TNF (Bu et al., 2015; Williams-Gray et al., 2016), IL-1β (Bu et al., 2015; Dursun et al., 2015; Hu et al., 2015) and IL-6 (Bu et al., 2015; Dursun et al., 2015; Williams-Gray et al., 2016), are elevated in the serum of PD patients (Qin et al., 2016). The gene discussed is TNF; the disease is Parkinson disease.