The changes in the gut microbiota result in the hypoactivity of N-methyl-d-aspartate (NMDA) and brain-derived neurotrophic factor (BDNF)/glial-cell derived neurotrophic factor (GDNF) receptors, which regulate brain plasticity, in schizophrenia patients [131,192]. The gene discussed is BDNF; the disease is schizophrenia.