A case of mitochondrial myopathy, lactic acidosis and complex I deficiency.
A 34-year-old man affected by exercise intolerance, mild proximal weakness and severe lactic acidosis is described. Muscle biopsy revealed mitochondrial abnormalities and an increase of cytochrome c oxidase histochemical reaction. Biochemical investigations on isolated muscle mitochondria as well as polarographic studies revealed a mitochondrial NADH-CoQ reductase (complex I) deficiency. Mitochondrial dysfunction was confirmed by 31P nuclear magnetic resonance spectroscopy. Immunological investigation showed a generalized reduction of all complex I polypeptides. Genetic analysis did not reveal mitochondrial DNA deletions. The biochemical defect was not present in the patient's muscle tissue culture. Metabolic measurements and functional evaluation showed a reduced mechanical efficiency during exercise.
Bet
L
L
Institute of Clinical Neurology, University of Milan, Italy.
Bresolin
N
N
Moggio
M
M
Meola
G
G
Prelle
A
A
Schapira
A H
AH
Binzoni
T
T
Chomyn
A
A
Fortunato
F
F
Cerretelli
P
P
D000140:Acidosis, Lactic / Q000209:etiology*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000328:Adult; D002478:Cells, Cultured; D004272:DNA, Mitochondrial / Q000032:analysis; D004797:Enzyme-Linked Immunosorbent Assay; D015444:Exercise / Q000502:physiology; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008931:Mitochondria, Muscle / Q000648:ultrastructure; D009132:Muscles / Q000378:metabolism / Q000648:ultrastructure; D009135:Muscular Diseases / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D016660:NAD(P)H Dehydrogenase (Quinone); D010101:Oxygen Consumption / Q000502:physiology; D010725:Phosphocreatine / Q000378:metabolism; D011808:Quinone Reductases / Q000172:deficiency*
D004272:DNA, Mitochondrial; D010725:Phosphocreatine; D000255:Adenosine Triphosphate; D016660:NAD(P)H Dehydrogenase (Quinone); D011808:Quinone Reductases