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Clinical manifestation of mitochondrial diseases in children
1Department of Pediatrics, Taichung Veterans General Hospital Taichung, Taiwan, R.O.C.
Insights
This study diagnosed mitochondrial diseases in fourteen children using clinical signs and muscle biopsy. Abnormal mitochondrial structures were key indicators across various syndromes affecting multiple organs.
Area of Science:
- Pediatric Neurology
- Mitochondrial Medicine
- Muscle Pathology
Background:
- Mitochondrial diseases are a group of heterogeneous genetic disorders.
- Diagnosis often relies on a combination of clinical presentation and specific pathological findings.
Purpose of the Study:
- To characterize clinical manifestations and muscle mitochondrial morphology in pediatric patients diagnosed with mitochondrial disease.
- To correlate clinical diagnoses with observed ultrastructural abnormalities in muscle mitochondria.
Main Methods:
- Retrospective analysis of fourteen pediatric patients diagnosed with mitochondrial disease.
- Evaluation of clinical data, including neurological and systemic involvement.
- Histopathological examination of muscle biopsies, focusing on mitochondrial morphology via electron microscopy.
Main Results:
- Diagnoses included Leigh syndrome, Menkes' syndrome, Kearns-Sayre syndrome, and various myopathies.
- Central nervous system and heart were commonly affected organs.
- Abnormal mitochondrial morphologies observed included abnormal accumulation and cristae patterns; ragged-red fibres were present in some patients.
- Elevated lactate levels post-glucose loading were noted in nine patients.
Conclusions:
- Pediatric mitochondrial diseases present with diverse clinical features and significant muscle pathology.
- Abnormal mitochondrial morphology is a crucial diagnostic marker in these conditions.
- Electron microscopy provides essential ultrastructural details for diagnosing mitochondrial disorders.
Abstract:
Fourteen patients (10 boys, 4 girls) aged from 4 months to 14 years old were diagnosed with mitochondrial disease based on the clinical manifestations together with abnormal muscle mitochondrial morphologies. Their clinical diagnoses included Leigh syndrome, three; Menkes' syndrome, three; Kearns-Sayre syndrome, two; myoclonic epilepsy with ragged fibres, one; and infant-onset progressive myoclonic epilepsy, one; fatal infantile mitochondrial myopathy, one; fatty acid oxidation defect, two; and myopathy with cardiopathy, one. Organs involved other than muscles included central nervous system, ten; heart, six; eye, two; liver, two; and kidney, two. Clinical manifestations varied to include hypotonia, seizures, myoclonus, mental retardation, nystagmus, ataxia, ptosis, ophthalmoplegia, retinal degeneration, muscle atrophy, spasticity etc. Nine had an abnormal rise in lactate after glucose loading. Ragged-red fibres were found in four patients. Abnormal mitochondrial morphology included abnormal accumulation, abnormal cristae pattern of tubular, concentric, or parallel form, some contained osmiophilic inclusion bodies. One patient of Leigh syndrome had had brain necropsy which showed intramyelin splitting of myelinated axons.