Adenyl cyclase 5, encoded by ADCY5, is a striatal-specific enzyme that converts adenosine triphosphate (ATP) into cyclic adenosine monophosphate (cAMP), an intracellular second messenger crucial for several molecular pathways. ADCY5 is a member of the membrane-bound adenylyl cyclase enzymes. Adenylyl cyclases mediate G protein-coupled receptor signaling through the synthesis of the second messenger cAMP. The activity of the encoded protein is stimulated by the Gs alpha subunit of G protein-coupled receptors and is inhibited by protein kinase A, calcium and Gi alpha subunits. Adenylyl cyclase 5 (ADCY5) mutations is associated with heterogenous syndromes: familial dyskinesia and facial myokymia; paroxysmal chorea and dystonia; autosomal-dominant chorea and dystonia; and benign hereditary chorea.