The present invention relates to three novel genes and polypeptides derived therefrom encoding ".alpha.2.delta.-C" and/or ".alpha.2.delta.-D" proteins which exist as a subunit in many calcium channels. The invention also describes methods for using the novel gene and polypeptides in the detection of genetic deletions of the gene, subcellular localization of the polypeptide, binding assays in connection with chemical databases, gene therapy.