PPARGC1A and polycystic ovary syndrome: Furthermore, consistent with the increase in mtDNA copy numbers, the expression levels of mitochondrial biogenesis-related genes, such as peroxisome proliferator-activated receptor (PPAR) gamma-co-activator 1a (PGC-1α), TFAM, and nuclear respiratory factor 1 (NRF-1) in iPSCs from patients with PCOS are high.