Connexin

Part of a group of major proteins of gap junctions that are important in the key process of intercellular communication in most cell types. The connexins are encoded by a large gene family, of which 15 human genes have been identified (as of this writing in 2001). Dominant mutations in the connexin molecules underlie some skin diseases or deafness or both disorders. Connexin mutations also underlie other disorders, including peripheral neuropathy and cataract formation. Connexin mutations are, for instance responsible for some of the inherited keratodermas. These are hereditary skin disorders characterized by thickened (hyperkeratotic) skin on the palms and soles. Mutations in four connexins have been demonstrated in epidermal disorders. In three of these connexins, certain mutations also result in sensorineural hearing loss (deafness).

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con·nex·in (kə-nekґsin) one of the protein subunits of a connexon, six connexins in hexagonal array making up a connexon. Each connexin contains four transmembrane α-helices and numerous connexin subtypes exist.