GJA1 is a member of the connexin gene family. Gap junction protein alpha 1 is a component of gap junctions, which are composed of arrays of intercellular channels that provide a route for the diffusion of low molecular weight materials from cell to cell. Gap junction protein alpha 1 is the major protein of gap junctions in the heart that are thought to have a crucial role in the synchronized contraction of the heart and in embryonic development. A related intronless pseudogene has been mapped to chromosome 5. Mutations in GJA1 have been associated with oculodentodigital dysplasia, autosomal recessive craniometaphyseal dysplasia and heart malformations.