Mitochondrial myopathy biomarkers

Mitochondrial myopathies comprise a heterogeneous group of disorders arising from structural or functional mitochondrial impairments that disrupt oxidative phosphorylation and cellular ATP production. The resulting energy deficit manifests not only in muscle but frequently leads to multi-systemic disease involving the brain, heart, kidneys, and endocrine system, creating a complex and often confounding clinical presentation. A critical, often overlooked aspect of their pathophysiology is that mitochondrial dysfunction extends far beyond bioenergetics. These organelles are vital hubs for biosynthetic pathways, calcium homeostasis, thermogenesis, apoptosis, and redox-sensitive signaling pathways that govern gene expression. The disruption of these integrated functions, whose molecular consequences are still being elucidated, is central to the disease's progression and heterogeneity. This clinical and molecular complexity contributes to significant diagnostic delay, with many remaining undiagnosed. Therefore, the development and strategic implementation of reliable biomarkers are essential. This review critically evaluates current and emerging biomarkers, proposing a diagnostic framework designed to improve diagnostic accuracy, limit unnecessary procedures, and ensure timely access to therapeutic interventions and genetic counseling.