Mitochondrial DNA copy number and pyrosequencing-based methylation profile in muscular dystrophies: a promising predictive tool

The database includes the raw data of the article “Mitochondrial DNA copy number and pyrosequencing-based methylation profile in muscular dystrophies: a promising predictive tool”. Muscular Dystrophies (MD) are genetic disorders characterized by progressive muscle weakness. Mutations in the DMD gene, encoding dystrophin, are a primary cause, leading to Duchenne (DMD) or Becker (BMD) muscular dystrophy. Mitochondrial dysfunction, including impaired ATP production, significantly contributes to MD pathology. Epigenetic mechanisms, particularly DNA methylation, regulate mitochondrial DNA (mtDNA) and influence mitochondrial function. This study investigated mtDNA D-loop methylation and mtDNA copy number in 24 muscle biopsies (6 BMD, 12 DMD, 6 controls) and 67 blood samples (18 BMD, 28 DMD, 21 controls). We found significantly lower D-loop methylation in blood samples of DMD and BMD patients compared to controls, with an opposite trend in muscle biopsies. mtDNA copy number was significantly reduced in both muscle and blood from patients across all mitochondrial genes analyzed. Notably, muscle mtDNA copy number effectively differentiated between DMD and BMD patients (AUC > 0.96), with mt-TL1 copy number showing perfect discrimination for DMD vs. controls (AUC = 1.0). In peripheral blood, D-loop methylation and mtDNA copy number showed good discriminatory power for MD patients vs. controls (AUC > 0.70), but not for distinguishing between DMD and BMD. These findings highlight significant tissue-specific and phenotype-specific alterations in mtDNA methylation and copy number in MD. Our results suggest that muscle mtDNA copy number could serve as a robust biomarker for differentiating MD phenotypes, while combined peripheral blood markers hold promise for less invasive diagnostic strategies for muscular dystrophies. Future studies with larger cohorts are needed to validate these findings and explore their functional implications.