Estrogen, as a sex hormone, has demonstrated efficacy in reducing the severity of experimental autoimmune encephalomyelitis in animal models of central nervous system (CNS) inflammation, as well as in clinical settings where treatment with estrogen derivatives correlated with decreased MRI-measured gadolinium-enhancing lesions in women with relapsing-remitting multiple sclerosis (RRMS) [32]. The gene discussed is PLXNA3; the disease is experimental autoimmune encephalomyelitis.