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.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Oftalmologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Ophthalmology (hsv//eng)

Keyword

Adolescent

DNA Mutational Analysis

Electron Transport

genetics

Electron Transport Complex IV

metabolism

Exercise Tolerance

genetics

Female

Humans

Mitochondrial Myopathies

complications

genetics

physiopathology

Muscle Fibers

metabolism

pathology

Muscle Weakness

genetics

physiopathology

Mutation

genetics

RNA

genetics

RNA

Transfer

Phe

genetics

Retina

pathology

physiopathology

Retinal Artery

pathology

physiopathology

Retinal Diseases

complications

genetics

physiopathology

Mitochondrial

Publication and Content Type

ref (subject category)

art (subject category)