Mitoredox shifts in mitochondrial dysfunction.

Mitochondrial dysfunction underlies a broad spectrum of primary and secondary disorders, yet current frameworks do not fully capture how diverse genetic, metabolic, and environmental stressors converge on shared pathological outcomes. Here, we propose that mitoredox shifts - bidirectional disruptions in mitochondrial redox homeostasis that alter mitochondrial quality control and genome-stability pathways - serve as a unifying axis linking oxidative stress, mitochondrial quality control failure, heteroplasmy dynamics, and regulated cell death. Both hyperactive and hypoactive mitochondrial states destabilize redox balance, altering PINK1/Parkin-dependent and receptor-mediated mitophagy, disrupting proteostasis, and reshaping mitochondrial network dynamics. These redox-driven perturbations influence the propagation of pathogenic mtDNA variants, modulate tissue-specific threshold effects, and bias cells toward apoptosis, ferroptosis, cuproptosis, and other regulated cell death pathways. We synthesize emerging evidence across mitochondrial genetics, bioenergetics, and redox signaling to outline how mitoredox shifts accelerate disease progression in both primary mitochondrial syndromes and secondary mitochondrial dysfunction. We further evaluate the expanding landscape of diagnostic biomarkers, including FGF21, GDF15, imaging-based oculomics, and high-throughput proteomic and genomic assays. In parallel, we highlight therapeutic strategies aimed at restoring redox balance, enhancing mitophagy, or shifting mitochondrial network composition by diluting dysfunctional organelles through mitochondrial transplantation. By emphasizing mitoredox imbalance as a recurrent feature of disease, this work synthesizes emerging diagnostic and therapeutic approaches across rare and common mitochondrial disorders.