Abstract for presentation at The Australian and New Zealand Association of Neurologists Annual Scientific Meeting 2007

Detection of large-scale deletions in mitochondrial DNA using DNA extracted from salivary samples

  • Dr Himesha Vandebona, Department of Neurogenetics, Kolling Institute of Medical Research, University of Sydney, Royal North Shore Hospital, Australia
  • Dr Con Yiannikas, Department of Neurology, Concord Hospital, Australia
  • A/Prof Carolyn Sue, Department of Neurogenetics, Kolling Institute of Medical Research, University of Sydney, Royal North Shore Hospital, Australia

    • Background: Large deletions in mitochondrial DNA (mtDNA) are found in patients with chronic progressive external ophthalmoplegia (CPEO). Southern blot analysis is the standard method to identify these mutations. Typically, muscle tissue is used for this type of analysis because deletions are often not found in blood and other sources of DNA do not provide adequate amounts of DNA for the test.
    Aim: To determine whether deletions in mtDNA can be detected in the DNA extracted from salivary samples from patients with CPEO.
    Methods: We collected salivary samples from 3 patients who were clinically diagnosed with CPEO. Samples were collected into Oragene vials (Geneworks Pty. Ltd, South Australia). DNA from saliva was extracted following the manufacturer’s instructions. DNA was also extracted from blood samples obtained from patients. Five micrograms of total DNA from blood and saliva of each patient were digested with BamH1 and SnaB1 restriction enzymes separately and used for Southern blot analysis. The DNA was hybridized with radio-labelled mitochondrial DNA probes.
    Results: We found large-scale deletions in the salivary samples of two patients. In the third we detected multiple mtDNA deletions. No mtDNA deletion was identified in the DNA extracted from the patients’ blood samples.
    Conclusion: We conclude that Southern blot analysis using salivary samples can successfully detect large-scale mtDNA deletions (>2kb) in patients with CPEO. Salivary samples are a convenient alternative source for screening of mtDNA large-scale deletions and may avoid the need for muscle biopsy in patients requiring genetic analysis for this condition.

    Conference Organiser - ICMS Pty Ltd