In a case-control study examining the oxidant/antioxidant balance and migraine characteristics (n = 44), the total non-enzymatic antioxidant capacity was found to be reduced in chronic migraine patients and a negative and significant correlation was reported between the number of days with headaches in a month and the values of the following variables including catalase antioxidant enzymes (r = −0.60, p < 0.001), superoxide dismutase (r = −0.50, p < 0.001), and the Trolox equivalent antioxidant capacity (r = −0.61, p < 0.001) (27). The gene discussed is CAT; the disease is migraine disorder.