Correlation between clinical and molecular features in two MELAS families

Andrea Martinuzzi, Luigi Bartolomei, Rosalba Carrozzo, Marialuisa Mostacciuolo, Costantino Carbonin, Vito Toso, Emma Ciafaloni, Sara Shanske, Salvatore DiMauro, Corrado Angelini

Research output: Contribution to journalArticlepeer-review


We describe the clinical, morphological, biochemical presentation in two MELAS families, and correlate it with the distribution and proportion of mitochondrial DNA carrying the A to G transition at nt 3243. Family A was characterized by late onset MELAS in two members, CPEO in one, and mild CNS involvement in another. 20-61% of mtDNA of affected and unaffected individuals was mutated in muscle, 2-18% in blood. There was no obvious correlation between clinical picture and proportion of mutated mtDNA. In family B full MELAS syndrome appeared only in the third generation, but the mutation was also detected in muscle of asymptomatic individuals of the first and second generation. The proportion of mutated mtDNA in blood, and to a lesser extent in muscle, correlated with the severity of the clinical presentation. The MELAS mutation is consistently detected in all asymptomatic maternal relatives of MELAS patients. We conclude that different clinical presentations of mitochondrial encephalomyopathy may coexist in the same family, and correlation between clinical severity and molecular abnormality is not always recognizable. Presence of the MELAS mutation in muscle and blood is a necessary but not sufficient condition for the expression of the typical MELAS phenotype.

Original languageEnglish
Pages (from-to)222-229
Number of pages8
JournalJournal of the Neurological Sciences
Issue number2
Publication statusPublished - 1992


  • Mitochondrial DNA
  • Mitochondrial encephalomyopathy

ASJC Scopus subject areas

  • Ageing
  • Clinical Neurology
  • Surgery
  • Neuroscience(all)
  • Developmental Neuroscience
  • Neurology

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