Association of the MELAS m.3243A>G mutation with myositis and the superiority of urine over muscle, blood and hair for mutation detection

J Clin Neurosci. 2009 Sep;16(9):1223-5. doi: 10.1016/j.jocn.2008.11.012. Epub 2009 Jun 6.


A patient with a known family history of mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS) due to the MT-TL1 m.3243A>G mutation presented with mild myalgia and very minor upper limb proximal muscle weakness. Muscle histology revealed low levels of cytochrome oxidase-negative fibres and non-specific myositis. Using the last "hot cycle" polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP), the MELAS MT-TL1 m.3243A>G mutation was only detected in urine, and not in hair, blood or skeletal muscle. This report highlights the need to screen various tissues to achieve an accurate mitochondrial genetic diagnosis and suggests the likelihood of myositis arising secondary to the MELAS MT-TL1 m.3243A>G mutation.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biopsy
  • DNA, Mitochondrial / genetics
  • Female
  • Hair / chemistry*
  • Humans
  • MELAS Syndrome / diagnosis
  • MELAS Syndrome / genetics*
  • MELAS Syndrome / urine*
  • Middle Aged
  • Muscle, Skeletal / chemistry*
  • Muscle, Skeletal / pathology
  • Mutation
  • Polymorphism, Restriction Fragment Length
  • Reverse Transcriptase Polymerase Chain Reaction


  • DNA, Mitochondrial