Postmortem studies have also revealed that the mRNA levels of BDNF, those of its receptor tyrosine kinase B (TrkB), and those of BDNF protein levels are decreased in the brains of patients with schizophrenia in specific regions like the prefrontal cortex and hippocampus, which are crucial for disease pathophysiology (Sugai et al. 2004; Thompson Ray 2011; Mohammadi et al. 2018b). The gene discussed is NTRK2; the disease is schizophrenia.