GJC2 and demyelinating disease: In demyelinating diseases, oligodendrocytic Cx32 and Cx47 are markedly down‐regulated in acute lesions and persistently absent, even in chronic lesions, whereas astrocytic Cx43 is down‐regulated in activated astroglia in acute lesions but markedly up‐regulated in chronic lesions, reflecting astrogliosis [12, 13, 14].