PDE4B and schizophrenia: What is important, a genome-wide linkage analysis [18] in ethnically homogeneous pedigrees has provided strong evidence for schizophrenia risk locus on chromosome 1p31.1, to which the nearest schizophrenia candidate gene is PDE4B. Additionally, they identified 14 SNPs of PDE4B gene associated with schizophrenia under a nominal P value of 0.05 [18].