CNP and schizophrenia: In addition, polymorphisms associated with schizophrenia are found in genes encoding oligodendrocyte transcription factor 2 (OLIG2; Georgieva et al., 2006), which is crucial for oligodendrocyte development, and 2’,3’-cyclic nucleotide 3’-phosphodiesterase (CNP), a structural myelin protein (Hagemeyer et al., 2012).