In the present study, it has been shown for the first time that an increase in the expression levels of DNMT1 and HCN1 genes in the somatosensory cortex and hippocampus, DNMT1, HCN1, and TH genes in the nucleus accumbens caused by a maternal methyl-enriched diet during the perinatal period is associated with the long-lasting (sustained) suppression of absence seizures and comorbid depression in offspring. The gene discussed is TH; the disease is major depressive disorder.