Genetics

This blog post examines a 2025 Molecular Neurobiology study that investigated the causal relationship between mitochondrial DNA copy number (mtDNA-CN) and multiple sclerosis progression using a bidirectional two-sample Mendelian randomization framework. The analysis found no evidence that mtDNA-CN directly drives disease progression, but it did identify evidence that worsening multiple sclerosis may contribute to reduced mtDNA-CN, supporting the view that mitochondrial dysfunction is more likely a consequence of progressive disease biology than an initiating cause. The post explains the study design, main findings, biological interpretation, strengths, limitations, and implications for the use of mtDNA-CN as a potential biomarker in multiple sclerosis research and clinical monitoring.