Arthritis groups displayed significantly reduced C I activity (29.7 ± 5.7 pmol/s/mL in OA and 12.8 ± 5.4 pmol/s/mL in RA) and reduced OxPhos (65.9 ± 7 in OA and 37.3 ± 8.2 pmol/s/mL in RA) in the presence of a saturating amount of ADP compared to the control group (39.2 ± 6.8 pmol/s/mL and 86 ± 15.5 pmol/s/mL, respectively). Here, NDUFB6 is linked to rheumatoid arthritis.