A novel mutation in the mitochondrial DNA tRNA Leu (UUR) gene associated with late-onset ocular myopathy.
We identified a novel G3283A transition in the mitochondrial DNA tRNA(Leu (UUR)) gene in a patient with ptosis, ophthalmoparesis and hyporeflexia. Muscle biopsy showed cytochrome oxidase positive ragged-red fibers, and defects of complexes I, III and IV of the mitochondrial respiratory chain. The mutation was heteroplasmic in muscle of the proband, being absent in her blood. Ragged-red fibers harbored greater levels of mutant genomes than normal fibers. The G3283A mutation affects a strictly conserved base pair in the TPsiC stem of the gene and was not found in controls, thus satisfying the accepted criteria for pathogenicity.
Maeso
E
E
Centro de Investigación, Hospital 12 de Octubre, Avda. de Córdoba km 5.4, 28041 Madrid, Spain.
Rueda
A
A
Jiménez
S
S
Del Hoyo
P
P
Martín
R
R
Cabello
A
A
Mendoza
L M
LM
Arenas
J
J
Campos
Y
Y
D000369:Aged, 80 and over; D004252:DNA Mutational Analysis / Q000379:methods; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D006801:Humans; D018482:Muscle, Skeletal / Q000737:chemistry / Q000378:metabolism; D009154:Mutation; D017246:Ophthalmoplegia, Chronic Progressive External / Q000235:genetics* / Q000473:pathology; D012356:RNA, Transfer, Leu / Q000235:genetics*
D004272:DNA, Mitochondrial; D012356:RNA, Transfer, Leu