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Low succinate dehydrogenase (SDH) activity in a patient with a hereditary myopathy with paroxysmal myoglobinuria
Author(s) -
LINDERHOLM H.,
ESSÉNGUSTAVSSON B.,
THORNELL L.E.
Publication year - 1990
Publication title -
journal of internal medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.625
H-Index - 160
eISSN - 1365-2796
pISSN - 0954-6820
DOI - 10.1111/j.1365-2796.1990.tb00191.x
Subject(s) - myoglobinuria , succinate dehydrogenase , myopathy , endocrinology , mitochondrial myopathy , medicine , mitochondrion , glycogenolysis , exercise intolerance , glycogen phosphorylase , lactate dehydrogenase , citric acid cycle , glycogen , biochemistry , chemistry , rhabdomyolysis , enzyme , metabolism , mitochondrial dna , heart failure , gene
. An unusual hereditary myopathy with paroxysmal myoglobinuria has been described previously. We have studied muscle biopsy specimens taken before and after exercise to exhaustion (24 min at 20–25 W) in a young woman with this condition. Marked glycogenolysis with lactate production and marked phosphagen breakdown (ATP + CP) were observed after exercise, and almost all type I fibres were found to be depleted of glycogen. Succinate dehydrogenase (SDH) activity was low, while the activities of 3‐OH‐acyl‐CoA‐dehydrogenase, phosphofructokinase, phosphorylase and lactate dehydrogenase were normal. On electron microscopy, the mitochondria showed abnormalities typical of mitochondrial myopathy. The findings in our patient suggest a limitation of mitochondrial function, probably related to SDH in the tricarboxylic acid cycle and complex II in the electron transport chain. This may explain the inability of ATP regeneration to keep pace with ATP utilization during exercise. Other metabolic defects may coexist.