Mitochondrial disease with hypertrophic cardiomyopathy

Mitochondrial disease with hypertrophic cardiomyopathy (Orphanet code 217587) is a group of rare genetic disorders in which defects in mitochondrial function lead to abnormal thickening of the heart muscle (hypertrophic cardiomyopathy, or HCM). Mitochondria are the energy-producing structures within cells, and when they malfunction, organs with high energy demands — particularly the heart, brain, skeletal muscles, and liver — are most severely affected. In this condition, the heart muscle becomes abnormally thick, which can impair the heart's ability to pump blood efficiently and may lead to heart failure, arrhythmias, or sudden cardiac events. Patients may present with symptoms such as shortness of breath, exercise intolerance, fatigue, poor feeding (in infants), failure to thrive, and signs of cardiac dysfunction. Because mitochondrial diseases are systemic, additional features may include skeletal muscle weakness (myopathy), developmental delay, lactic acidosis, and neurological abnormalities. The severity and age of onset can vary widely depending on the specific underlying genetic defect. Some patients present in the neonatal or infantile period with severe, rapidly progressive disease, while others may have a more indolent course. There is currently no cure for mitochondrial disease with hypertrophic cardiomyopathy. Treatment is largely supportive and symptomatic, focusing on managing heart failure with standard cardiac medications (such as beta-blockers or ACE inhibitors), monitoring for arrhythmias, and addressing other organ involvement. Nutritional supplementation with cofactors such as coenzyme Q10, L-carnitine, and B vitamins is sometimes used, though evidence for their efficacy remains limited. In severe cases, heart transplantation may be considered, although the multisystem nature of mitochondrial disease can complicate candidacy. Genetic counseling is recommended for affected families.

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