NDUFC2 is a structural subunit of mitochondrial respiratory chain complex I required for assembly of the membrane arm, and its loss compromises oxidative phosphorylation while driving downstream oxidative and inflammatory signaling (PMID:26888427, PMID:32969598). Bi-allelic loss-of-function variants in NDUFC2 produce severe defects in complex I activity, subunit expression, and assembly, with complexome profiling localizing the block to stalled biogenesis of the ND2 module of the membrane arm; lentiviral re-expression of wild-type NDUFC2 restores assembly, establishing it as causal and sufficient for this assembly step (PMID:32969598). Genetic disruption reduces complex I activity, mitochondrial membrane potential, and ATP while elevating reactive oxygen species and inflammation, accompanied by loss of cristae and ultrastructural mitochondrial damage that is exacerbated by high-NaCl and LPS stress and counteracted by resveratrol (PMID:26888427, PMID:28973657). This NDUFC2-dependent mitochondrial output sits upstream of vascular and cardiac pathology: loss in endothelial and smooth muscle cells impairs viability and angiogenesis and induces atherogenic markers (PMID:30808603), silencing in cardiomyocytes drives hypertrophy via SIRT3-AMPK-AKT-MnSOD signaling (PMID:37558995), and NDUFC2 overexpression suppresses NLRP3 inflammasome activation and endothelial-mesenchymal transformation in ischemia-reperfusion injury (PMID:37506315).