Mitochondrial myopathy with exercise intolerance and retinal dystrophy in a sporadic patient with a G583A mutation in the mt tRNA(phe) gene.
We describe a second patient with the 583G>A mutation in the tRNA(phe) gene of mitochondrial DNA (mtDNA). This 17-year-old girl had a mitochondrial myopathy with exercise intolerance and an asymptomatic retinopathy. Muscle investigations showed occasional ragged red fibers, 30% cytochrome c oxidase (COX)-negative fibers, and reduced activities of complex I+IV in the respiratory chain. The mutation was heteroplasmic (79%) in muscle but undetectable in other tissues. Analysis of single muscle fibers revealed a significantly higher level of mutated mtDNA in COX-negative fibers. Our study indicates that the 583G>A mutation is pathogenic and expands the clinical spectrum of this mutation.
Darin
N
N
Department of Pediatrics, Sahlgrenska University Hospital, Göteborg, Sweden. niklas.darin@vgregion.se
Kollberg
G
G
Moslemi
A-R
AR
Tulinius
M
M
Holme
E
E
Grönlund
M Andersson
MA
Andersson
S
S
Oldfors
A
A
D000293:Adolescent; D004252:DNA Mutational Analysis; D004579:Electron Transport / Q000235:genetics; D003576:Electron Transport Complex IV / Q000378:metabolism; D017079:Exercise Tolerance / Q000235:genetics; D005260:Female; D006801:Humans; D017240:Mitochondrial Myopathies / Q000150:complications / Q000235:genetics* / Q000503:physiopathology; D018485:Muscle Fibers, Skeletal / Q000378:metabolism / Q000473:pathology; D018908:Muscle Weakness / Q000235:genetics / Q000503:physiopathology; D009154:Mutation / Q000235:genetics*; D012313:RNA / Q000235:genetics*; D000077278:RNA, Mitochondrial; D012360:RNA, Transfer, Phe / Q000235:genetics*; D012160:Retina / Q000473:pathology / Q000503:physiopathology; D012161:Retinal Artery / Q000473:pathology / Q000503:physiopathology; D012164:Retinal Diseases / Q000150:complications / Q000235:genetics* / Q000503:physiopathology
D000077278:RNA, Mitochondrial; D012360:RNA, Transfer, Phe; D012313:RNA; D003576:Electron Transport Complex IV