Another important comorbidity to consider is hypovitaminosis D. A study evaluated the vitamin D, vitamin D-binding protein, vitamin D receptor (VITDR), high-sensitivity C-reactive protein, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), total antioxidant status (TAS), total oxidant status, and oxidative stress index values in 50 RRMS patients with migraine, 50 RRMS patients without migraine, and 50 healthy volunteers. The gene discussed is GC; the disease is migraine disorder.