Human genetics
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We recently reported the results of a genome-wide association study (GWAS) of schizophrenia in the Japanese population. In that study, a single nucleotide polymorphism (SNP) (rs3106653) in the KCNJ3 (potassium inwardly rectifying channel, subfamily J, member 3) gene located at 2q24.1 showed association with schizophrenia in two independent sample sets. KCNJ3, also termed GIRK1 or Kir3.1, is a member of the G protein-activated inwardly rectifying K(+) channel (GIRK) group. ⋯ Next, we analyzed transcript levels in the dorsolateral prefrontal cortex of postmortem brains from patients with schizophrenia and bipolar disorder and from healthy controls, using real-time quantitative RT-PCR. We found significantly lower KCNJ3 expression in postmortem brains from schizophrenic and bipolar patients compared with controls. These data suggest that the KCNJ3 gene is genetically associated with schizophrenia in Asian populations and add further evidence to the "channelopathy theory of psychiatric illnesses".