Background and Purpose The pathogenesis of mitochondrial disease (MD) involves the disruption of cellular energy metabolism, which results from defects in the mitochondrial respiratory chain complex (MRC). We investigated whether infants with MRC I defects showed ultrastructural changes in skeletal muscle. Methods Twelve infants were enrolled in this study. They were initially evaluated for unexplained neurodegenerative symptoms, myopathies, or other progressive multiorgan involvement, and underwent muscle biopsies when MD was suspected. Muscle tissue samples were subjected to biochemical enzyme assays and observation by transmission electron microscopy. We compared and analyzed the ultrastructure of skeletal muscle tissues obtained from patients with and without MRC I defects. Results Biochemical enzyme assays confirmed the presence of MRC I defects in 7 of the 12 patients. Larger mitochondria, lipid droplets, and fused structures between the outer mitochondrial membrane and lipid droplets were observed in the skeletal muscles of patients with MRC I defects. Conclusions Mitochondrial functional defects in MRC I disrupt certain activities related to adenosine triphosphate synthesis that produce changes in the skeletal muscle. The ultrastructural changes observed in the infants in this study might serve as unique markers for the detection of MD.
Bibliographical noteFunding Information:
This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (grant no. NRF-2015R1C1A1A020 37153) and by a faculty research grant from Yonsei University College of Medicine for 2010 (no. 6-2010-0172). The authors are grateful to all staff members, doctors, and statistical consultants who were involved in this study.
All Science Journal Classification (ASJC) codes
- Clinical Neurology