Mitochondrial myopathies, fatal infantile

This complex contains 11 polypeptide subunits of which only one is encoded by mtDNA. Defects of complex III are relatively uncommon and clinical presentations vary. Fatal infantile encephalomyopathies have been described in which severe neonatal lactic acidosis and hypotonia are present along with generalized amino aciduria, a Fanconi syndrome of renal insufficiency and eventual coma and death. Muscle biopsy findings may be uninformative since abnormal mitochondrial distribution is not seen, i.e., there are no ragged-red fibers. Other patients present with pure myopathy in later life and the existence of tissue-specific subunits in complex III has been suggested since one of these patients was shown to have normal complex 111 activity in lymphocytes and fibroblasts. 

The condition known as fatal infantile mitochondrial myopathy and renal dysfunction involves severe diminution or absence of most oxidoreductases of the respiratory chain. MELAS (mitochondrial encephalopathy, lactic acidosis, and stroke) is an inherited condition due to NADHiubiquinone oxidoreductase (complex I) or cytochrome oxidase deficiency. It is caused by a muta-... 

NING, C., KUHARA, T INOUE, Y, ZHANG, C.H., MATSUMOTO, M., SHINKA, T., FURUMOTO, T., YOKOTA, K., MATSUMOTO, I., Gas chromatographic mass spectrometric metabolic profiling of patients with fatal infantile mitochondrial myopathy with De Toni-Fanconi-Debre syndrome, Acta Paediatrica Japonica, 1996,38,661-666. 

Ml 8. Miiller-Hocker, J., Ibel, H., Paetzke, I., Deufel, T., Endres, W., Kadenbach, B., Gokel, J. M., and Hubner, G., Fatal infantile mitochondrial myopathy and myopathy with heterogeneous tissue expression of combined respiratory chain deficiencies. Virchows Arch. A Pathol. Anat. Histopathol. 419, 55-362 (1991). 

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