Mitochondrial DNA analysis in ocular myopathy. Observations in 29 Portuguese patients

Laura Vilarinho, Filippo M. Santorelli, M. L. Cardoso, Teresa Coelho, António Guimarães, Paula Coutinho

Research output: Contribution to journalArticlepeer-review


We analyzed 29 patients with progressive external ophthalmoparesis (PEO) either alone or as part of a multisystem disorder. Ragged-red fibers were very abundant (10-20%) in 15 patients, and many of them were also cytochrome c oxidase-negative. Biochemical analysis of the respiratory chain showed partial defects of single or multiple complexes in 18 patients (64%). Eleven PEO patients (38%) harbored single large-scale mtDNA deletions in muscle, which averaged 5.4 kb in size and 47% in relative abundance. One PEO patient harbored the A3243G mutation (MELAS mutation) in muscle (63%). Our findings, the first reported in Portuguese patients, confirm that single large-scale mtDNA deletions are a significant cause of PEO. Although ophthalmoparesis was the main clinical feature in the majority of patients, the clinical spectrum is broad, ranging from severe encephalopathy of childhood to a milder, though disabling, muscle weakness in adults.

Original languageEnglish
Pages (from-to)148-153
Number of pages6
JournalEuropean Neurology
Issue number3
Publication statusPublished - Apr 1998


  • Deletion
  • Mitochondria
  • mtDNA
  • PEO

ASJC Scopus subject areas

  • Clinical Neurology


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