The protein encoded by this gene is a cyclic nucleotide phosphodiesterase (PDE) that catalyzes the hydrolysis of the second messenger cAMP. The encoded protein, which does not hydrolyze cGMP, is resistant to several PDE inhibitors. Defects in this gene are a cause of autosomal dominant striatal degeneration (ADSD). Several transcript variants encoding different isoforms have been found for this gene.[provided by RefSeq, Jul 2010].