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MELAS of infantile onset: mitochondrial angiopathy or cytopathy?
Abstract:
An 83-day-old male infant had convulsions, hypertrophic cardiomyopathy, and lactic acidosis. Cranial computed tomography revealed low-density areas in both parieto-occipital lobes and in the left temporal lobe. Muscle biopsy did not reveal ragged-red fibers, but abnormal mitochondria were found in the capillary endothelial cells as well as in the muscle fibers. At 5 months of age, the patient developed purpura on the soles and palms. Skin biopsy showed degeneration of the endothelial cells with abnormal mitochondria in the arterioles and capillaries. Myelinated nerves in the skin had vacuolated axons with swollen mitochondria, and their myelin sheaths showed vacuolation. At 9 months of age, he died of heart failure, and autopsy revealed abnormal mitochondria in the myocardium but not in the coronary vessels. Our findings indicate that the symptoms of the mitochondrial encephalopathy, myopathy, lactic acidosis, and strokelike episodes (MELAS) syndrome cannot be fully explained by the mitochondrial angiopathy alone.
Insights
This study details a case of mitochondrial encephalopathy, myopathy, lactic acidosis, and strokelike episodes (MELAS) in an infant. Findings suggest MELAS symptoms extend beyond mitochondrial angiopathy, highlighting complex pathology.
Area of Science:
- Neurology
- Pediatrics
- Mitochondrial Diseases
Background:
- Mitochondrial encephalopathy, myopathy, lactic acidosis, and strokelike episodes (MELAS) syndrome is a complex disorder.
- Understanding the full spectrum of MELAS pathology is crucial for diagnosis and treatment.
Observation:
- An infant presented with seizures, hypertrophic cardiomyopathy, and lactic acidosis.
- Cranial CT showed brain lesions; muscle and skin biopsies revealed abnormal mitochondria in various cell types, including endothelial and muscle cells.
- Autopsy confirmed myocardial mitochondrial abnormalities, but not in coronary vessels.
Findings:
- Abnormal mitochondria were identified in muscle fibers, capillary endothelial cells, and skin arterioles/capillaries.
- Neuropathological findings included vacuolated axons and demyelination in skin nerves.
- The infant's presentation and autopsy results indicate MELAS involves more than just mitochondrial angiopathy.
Implications:
- The case expands the understanding of MELAS syndrome's multi-systemic involvement.
- Findings underscore the need for comprehensive diagnostic approaches in suspected MELAS cases.
- Further research is warranted to elucidate the complete pathophysiology of MELAS.