PDE4D and bipolar disorder: From theliterature we know that Plexin C1 receptor is a tumor suppressor gene formelanoma [33], NOTCH4 isinvolved in schizophrenia [34], Phosphodiesterase 4D (PDE4D) is associated with ischemicstroke [35], HLA-DRA isone of the HLA class II alpha chain genes that plays a central role in antigenprocessing, and neuregulin 1 (NRG1) has been implicated in diseases such ascancer, schizophrenia and bipolar disorder [36].