Key result
Novel homoplasmic m.9997T>C mitochondrial variant linked to early-onset hypertrophic cardiomyopathy and arrhythmias.
Why the study?
Mitochondrial cardiomyopathy presents diagnostic and therapeutic challenges due to genetic heterogeneity and variable clinical phenotypes.
Case Report (n=1)
The study supports the pathogenic role of the homoplasmic m.9997T>C variant in maternally inherited hypertrophic cardiomyopathy, highlighting the importance of tissue-specific genetic analysis in mitochondrial disorders.
m.9997T>C case extends MCM genetic spectrum; leaves open pathogenicity and clinical utility pending larger studies.
Background Mitochondrial cardiomyopathy (MCM), a common subtype of mitochondrial disorders accounting for 20-40% of cases, presents significant diagnostic and therapeutic challenges due to genetic heterogeneity and variable clinical phenotypes. Methods We conducted a comprehensive analysis of the clinical, histopathological, molecular, and genetic characteristics of a 23-year-old male with maternally inherited hypertrophic cardiomyopathy (HCM) associated with the homoplasmic m.9997 T > C variant. Results The patient exhibited early-onset exercise intolerance, arrhythmias, and cardiac dysfunction. Cardiac Magnetic Resonance Imaging confirmed asymmetric HCM with left ventricular enlargement. Genetic analysis identified a homoplasmic m.9997T > C variant across multiple tissues (blood, urine, mucosa, muscle). Muscle biopsy revealed typical mitochondrial abnormalities, and reduced expression of complex IV subunits. Conclusion Our findings support the pathogenic association of the homoplasmic m.9997T > C variant in HCM and highlight the clinical significance of homoplasmic mtDNA mutations in tissue-specific mitochondrial disorders, contributing to the broader understanding of homoplasmic mutations in mitochondrial disease.
No takes yet. Share an insight, caveat, or question.
Wang et al. (2026) conducted a case report in Hypertrophic cardiomyopathy (HCM) (n=1). Homoplasmic m.9997T>C variant was evaluated. The homoplasmic m.9997T>C variant is pathogenically associated with hypertrophic cardiomyopathy, presenting with early-onset exercise intolerance, arrhythmias, and mitochondrial abnormalities.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: