GDF15 and Mitochondrial myopathy: GDF-15 is a cytokine distributed in many organs, and it is considered a general biomarker of oxidative stress and inflammation-induced damage in mitochondrial myopathies.66 Several studies evidenced increased levels of this factor in the blood of mitochondrial patients, proposing it as a useful biomarker for these pathologies, especially for diseases due to defective mtDNA translation or maintenance.