Several clinical in vitro (the blood samples of 10 PD patients) and in vivo (n = 70 PD patients) studies reported the therapeutic effects of PBM (632.8 nm; 500 mW/cm2) on enzyme activity of monoamine oxidase B (MAO B), Cu/Zn-superoxide dismutase (Cu/Zn-SOD), Mn-SOD, and catalase in blood from PD patients [96,97]. The gene discussed is SOD2; the disease is Parkinson disease.