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An abnormal exercise test response revealing a respiratory chain complex III deficiency
Author(s) -
Mousson B.,
Collombet J. M.,
Dumoulin R.,
Carrier H.,
Flocard F.,
Bouzidi M.,
Godinot C.,
Maire I.,
Mathieu M.,
Quard S.
Publication year - 1995
Publication title -
acta neurologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.967
H-Index - 95
eISSN - 1600-0404
pISSN - 0001-6314
DOI - 10.1111/j.1600-0404.1995.tb00451.x
Subject(s) - muscle biopsy , respiratory chain , sarcolemma , mitochondrial myopathy , exercise intolerance , anaerobic exercise , medicine , endocrinology , ubiquinol , respiratory system , myopathy , mitochondrion , chemistry , biology , biochemistry , cytochrome c , biopsy , physiology , coenzyme q – cytochrome c reductase , myocyte , heart failure , mitochondrial dna , gene
A 29‐year‐old man with a progressive exertional muscle intolerance since childhood was referred for incremental exercise test on a bicycle ergometer. The response pattern suggested a mitochondrial myopathy: that is, a greatly reduced maximum oxygen consumption with appropriate heart rate increase and an anaerobic threshold point reached early. The metabolic investigation in plasma revealed an abnormal oxidoreduction status (hyperlactataemia and high lactate/pyruvate ratio) at rest and after a carbohydrate rich meal. The histochemical examination of a muscle biopsy revealed red granular deposits under the sarcolemma for all type 1 fibers. Oxypolarographic and enzymological studies of the mitochondrial respiratory chain in both isolated mitochondria and muscle homogenate demonstrated a marked deficiency of ubiquinol cytochrome c reductase (complex III) activity.