Labruijere et al. compared the methylation levels of calcitonin-related peptide alpha (Calca), receptor activity-modifying protein 1 (Ramp1), calcitonin receptor component protein, calcitonin receptor-like receptor, upstream stimulating factor 2, estrogen receptor 1, G-protein-coupled estrogen receptor 1, nitric oxide synthase 3, and methylenetetrahydrofolate reductase (Mthfr) genes between migraine-related tissues (dura mater, TG, and trigeminal caudal nucleus) and peripheral control tissues (aorta and leukocytes) in rats [41]. Here, MTHFR is linked to migraine disorder.