Mitochondrial respiratory-chain defects presenting as nonspecific features in children.
Patients with mitochondrial respiratory-chain defects frequently exhibit lactic acidosis, ragged red fibers in skeletal muscle samples, and abnormal enzyme assays for the respiratory-chain complex. However, ragged red fibers and lactic acidosis are not always seen in all patients with mitochondrial respiratory-chain defects. We have encountered six children with biochemically proven respiratory chain defects, but typical ragged red fibers were not found in all six patients, and only five patients had increased serum lactate levels. Initially, they present with nonspecific features. However, persistent or progressive clinical features or multiple organ involvement eventually led to the diagnosis of respiratory-chain defects in these patients. Mitochondrial respiratory-chain defects should be considered in the differential diagnosis when persistent, progressive features and especially multiple organ involvement occur.
Department of Pediatrics, College of Medicine and Public Health, Ohio State University, Columbus, USA. ctsao@chi.osu.edu
C Y
CY
Tsao
J R
JR
Mendell
W D
WD
Lo
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M
Luquette
J
J
Rusin
D000140:Acidosis, Lactic / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D001706:Biopsy; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D004579:Electron Transport / Q000235:genetics / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D017241:MELAS Syndrome / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D017243:MERRF Syndrome / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D008297:Male; D017237:Mitochondrial Encephalomyopathies / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D018482:Muscle, Skeletal / Q000473:pathology; D009460:Neurologic Examination; D012307:Risk Factors