Unusual features of mitochondrial degeneration in skeletal muscle of patients with nuclear complex I mutation
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We examined the histopathological finding in muscle of four patients with known nuclear mutations of complex I subunits. No ragged-red fibers were present, and the only abnormal finding on light microscopy was universal small fibers in three of them. At the ultrastructural level, evidence of mitochondrial degeneration was observed in the form of lipofuscin formation in a case with NDUFS2 mutation and in the form of concentric laminated bodies in a case with NDUFS8 mutation.
Among the mitochondrial disorders, complex I deficiency is encountered frequently. The first mutation in the nuclear-encoded complex I gene was found in the NDUFS8 in a patient with Leigh-like presentation . Subsequently, systematic sequencing analysis resulted in the identification of mutations in NDUFS1, NDUFS2, NDUFS4, NDUFS7, NDUFV1, and NDUFV2 genes, suggestive of a high prevalence of mutations in genes encoding for catalytic subunits in complex I .
Fresh quadriceps muscle biopsies were performed in four...
KeywordsDuchenne Muscular Dystrophy Mitochondrial Disorder Histological Hallmark Nuclear Mutation Thyrotoxic Periodic Paralysis
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