MT-ND3 and supranuclear palsy, progressive, 1: Interestingly, in PSP-RS patients, ND3-CN levels tended to increase with age, potentially reflecting an age-related compensatory mitochondrial response to chronic neuroinflammation.<h4>Conclusions</h4>Our findings support the involvement of mitochondrial dysfunction in PSP pathogenesis, suggesting that peripheral mtDNA-CN may serve as a non-invasive biomarker for disease monitoring.