biostudies-literatureZanini GFondazione Cassa di Risparmio di ModenaEuropean Union-Next Generation EU, Mission 6, Component 21433https://www.ebi.ac.uk/biostudies/studies/S-EPMC12468903biostudies-literatureUnknown14(18)Mitochondrial dysfunction is a key pathological hallmark in amyotrophic lateral sclerosis (ALS), yet the role of circulating cell-free mitochondrial DNA (Cf-mtDNA) as a biomarker remains unclear. This study aimed to investigate serum Cf-mtDNA levels in ALS patients compared to healthy controls and explore its associations with disease biomarkers, clinical progression, and survival. We conducted a case-control study measuring Cf-mtDNA levels in serum samples from 54 ALS patients and 36 age- and sex-matched healthy controls using quantitative droplet digital PCR. Correlations between Cf-mtDNA levels and clinical features, neurofilament concentrations, inflammatory indices, and survival were assessed. The average Cf-mtDNA level in ALS patients was 2,426,315 copies/mL of serum (IQR: 865000-247CellsCirculating Serum Cell-Free Mitochondrial DNA in Amyotrophic Lateral Sclerosis.PMC12468903Neurobiobanca di ModenaCUP F93C24000310005Gianferrari GZanini GBanchelli FGhezzi ASimonini CPinti MZucchi EMandrioli JMartinelli ISinigaglia GfalseCirculating Serum Cell-Free Mitochondrial DNA in Amyotrophic Lateral Sclerosis.Mitochondrial dysfunction is a key pathological hallmark in amyotrophic lateral sclerosis (ALS), yet the role of circulating cell-free mitochondrial DNA (Cf-mtDNA) as a biomarker remains unclear. This study aimed to investigate serum Cf-mtDNA levels in ALS patients compared to healthy controls and explore its associations with disease biomarkers, clinical progression, and survival. We conducted a case-control study measuring Cf-mtDNA levels in serum samples from 54 ALS patients and 36 age- and sex-matched healthy controls using quantitative droplet digital PCR. Correlations between Cf-mtDNA levels and clinical features, neurofilament concentrations, inflammatory indices, and survival were assessed. The average Cf-mtDNA level in ALS patients was 2,426,315 copies/mL of serum (IQR: 865000-2472025-01-01T00:00:00Z2025 Sep2026-05-01T03:21:02.922Z2026-05-01T03:10:59.078ZS-EPMC124689034100239810.3390/cells14181433