PDE4B and schizophrenia: Another case-control study [23] revealed that several SNPs within PDE4B gene including rs1354064, rs4320761, rs1040716, rs910694, rs1321177, rs2144719 and rs783038 were significantly associated with schizophrenia in Caucasian American population; in addition, rs599381, rs1040716 and rs910694 were shown to be significantly associated with schizophrenia in African American population.