Of the various PDE4 isoforms, those encoded by PDE4B have been most closely associated with schizophrenia and major affective disorders and have been shown to interact directly with DISC1, a protein implicated in neurodevelopment, nuclear functions, and susceptibility to schizophrenia in humans [160,161,162,163,164]. The gene discussed is PDE4A; the disease is schizophrenia.