Labruijere et al. showed that the methylation of genes associated with migraines—CRCP (CGRP receptor component), CALCRL (calcitonin receptor like receptor), ESR1 (estrogen receptor 1), and NOS3 (nitric oxide synthase 3)—was tissue-specific in female rats and the methylation of these genes in leukocytes did not correlate to methylation in other tissues [80]. The gene discussed is ESR1; the disease is migraine disorder.