[86] also found that the expression of PGC‐1α and its downstream target genes, such as nuclear respiratory factor 1 (NRF1) and mitochondrial transcription factor A (TFAM), is downregulated in blood monocytes of patients with depression, indicating that mitochondrial biogenesis disorder caused by low PGC‐1α expression may be a pathogenesis of depression. Here, TFAM is linked to major depressive disorder.