NRF1 and fragile X syndrome: Genes other than those involved in mitochondrial biogenesis and respiration have also been shown to be regulated by NRF-1 and NRF-2, such as the human FMR1 gene associated with fragile X syndrome [53]; reported functions of NRF-2/GABP include regulating B lymphocyte and myeloid development [52], [54], cell cycle progression [55], and formation of neuromuscular junctions [56].