Cyclic nucleotide phosphodiesterases (PDEs) catalyze hydrolysis of the cyclic nucleotides cAMP and cGMP to the corresponding nucleoside 5-prime-monophosphates. Mammalian PDEs have been classified into several families based on their biochemical properties. Members of the PDE1 family, such as PDE1C, are calmodulin (see MIM 114180)-dependent PDEs (CaM-PDEs) that are stimulated by a calcium-calmodulin complex (Repaske et al., 1992 [PubMed 1326532]).[supplied by OMIM, Oct 2009]