SOD1 and amyotrophic lateral sclerosis: Considering that mitochondrial function can vary due to changes in mitochondrial protein content, including in mitochondrial complexes, we further investigated the expression of NRF1. Our study demonstrated a significant decrease in NRF1 expression in ALS PBMCs (Fig. 3b), a finding that corroborates previous data in the literature in which a reduction in NRF1 expression in the spinal cord and muscles from ALS patients and SOD1-G93A animal models was shown [135, 137].