Mitochondrial Complex I Deficiency Clinical Trials 2026 — Find Recruiting Studies

About Mitochondrial Complex I Deficiency

Mitochondrial complex I deficiency is the most common defect of the mitochondrial respiratory chain and encompasses a heterogeneous group of disorders caused by mutations in any of the 44 subunit genes or numerous assembly factor genes of NADH:ubiquinone oxidoreductase. Clinical presentations range from neonatal lactic acidosis and fatal multiorgan failure to Leigh syndrome, MELAS, or isolated exercise intolerance in older individuals. Biochemical confirmation requires enzyme activity assay in muscle or fibroblasts, as blood-based assays are unreliable.

Common Clinical Features

Lactic acidosis Hypotonia and muscle weakness Leigh syndrome features (in early-onset cases) Encephalopathy and developmental regression Cardiomyopathy Liver dysfunction Exercise intolerance in milder phenotypes

Clinical Trial Eligibility Tips

What to know before applying to Mitochondrial Complex I Deficiency trials.

Biochemical diagnosis requires demonstration of complex I enzyme deficiency in muscle biopsy or cultured fibroblasts; blood enzyme assays are insufficient for most trial eligibility criteria.

Genetic confirmation via comprehensive mitochondrial gene panel or whole exome sequencing with functional validation is increasingly mandated; include both mtDNA and nuclear DNA testing.

Given the broad clinical spectrum, trials are often phenotype-specific (e.g., Leigh syndrome, cardiomyopathy); identify the predominant presenting phenotype to find the most relevant study.