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Mitochondrial cytochrome deficiency presenting as a myopathy with hypotonia, external ophthalmoplegia, and lactic acidosis in an infant and as fatal hepatopathy in a second cousin
Author(s) -
Boustany Rosemary N.,
Aprille June R.,
Halperin John,
Levy Harvey
Publication year - 1983
Publication title -
annals of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.764
H-Index - 296
eISSN - 1531-8249
pISSN - 0364-5134
DOI - 10.1002/ana.410140411
Subject(s) - lactic acidosis , mitochondrial myopathy , cytochrome c oxidase , mitochondrion , medicine , endocrinology , myopathy , biology , hypotonia , muscle biopsy , cytochrome , biochemistry , biopsy , mitochondrial dna , enzyme , gene
Fatal infantile mitochondrial myopathy with lactic acidosis, morphologically abnormal mitochondria, deficient cytochromes aa 3 and b, and a Fanconi‐like aminoaciduria has been described. We report two infants, second cousins, with a similar fatal mitochondrial disorder, the cytochrome deficiency limited to skeletal muscle in one child and to liver in the other. The first child at 3 months of age had weight loss, hypotonia, external ophthalmoplegia, and a severe lactic acidosis with a high lactate/pyruvate ratio. Electron microscopy of muscle showed marked proliferation of enlarged mitochondria, many containing concentric rings of cristae. In skeletal muscle mitochondria, cytochromes aa 3 and b were not detectable but cytochrome cc was found to be normal by spectroscopy. Cytochrome c oxidase activity was less than 1% of normal. Mitochondria from kidney, liver, heart, lung, and brain examined postmortem had normal cytochromes and preserved cytochrome c oxidase activity. The second cousin at 5 months of age had weighty loss and hepatomegaly but no systemic lactic acidosis. Liver biopsy showed hepatocytes packed with enlarged mitochondria. The liver mitochondria showed deficient cytochromes aa 3 and b postmortem, and cytochrome c oxidase activity was less than 10% of normal. Kidney mitochondria had normal cytochromes. Muscle was not studied. The mitochondrial abnormality in the two cousins presumably is related. Unexplained are the mode of genetic transmission or environmental exposure and the apparent involvement of a single different organ in each child.