Connexins in health and disease

Gap junctions or hemichannels are expressed on all cells in our body, and have a highly significant role in homeostasis and in disease states. There are 21 connexins found in humans and they have distinct characteristics that compensate for each other. The anatomical expression pattern also differs between each connexin; some of them are expressed together and some are not. Genetically mutated connexin genes induce inheritable diseases, but acquired disorders can also be caused by primary or secondary connexin dysfunctions. In the central nervous system, glial cells are the main connexin-expressing cells. They utilize connexin gap junctions to assemble glial networks. The present review not only describes the basic structures and functions of connexins, it also examines the relationships between connexins and their role in disease pathology.