Mitochondrial DNA triplication and punctual mutations in patients with mitochondrial neuromuscular disorders

Biochem Biophys Res Commun. 2016 Apr 29;473(2):578-85. doi: 10.1016/j.bbrc.2016.03.126. Epub 2016 Mar 28.


Mitochondrial diseases are a heterogeneous group of disorders caused by the impairment of the mitochondrial oxidative phosphorylation system which have been associated with various mutations of the mitochondrial DNA (mtDNA) and nuclear gene mutations. The clinical phenotypes are very diverse and the spectrum is still expanding. As brain and muscle are highly dependent on OXPHOS, consequently, neurological disorders and myopathy are common features of mtDNA mutations. Mutations in mtDNA can be classified into three categories: large-scale rearrangements, point mutations in tRNA or rRNA genes and point mutations in protein coding genes. In the present report, we screened mitochondrial genes of complex I, III, IV and V in 2 patients with mitochondrial neuromuscular disorders. The results showed the presence the pathogenic heteroplasmic m.9157G>A variation (A211T) in the MT-ATP6 gene in the first patient. We also reported the first case of triplication of 9 bp in the mitochondrial NC7 region in Africa and Tunisia, in association with the novel m.14924T>C in the MT-CYB gene in the second patient with mitochondrial neuromuscular disorder.

Keywords: MT-ATP6; Mitochondrial duplication; Mitochondrial mutations; m.14924T>C; m.9157G>A; mtDNA.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Child
  • Cytochromes b / chemistry
  • Cytochromes b / genetics
  • DNA, Mitochondrial / genetics*
  • Female
  • Genes, Mitochondrial
  • Humans
  • Male
  • Mitochondria / genetics*
  • Mitochondria / pathology
  • Mitochondrial Diseases / genetics*
  • Mitochondrial Diseases / pathology
  • Mitochondrial Proton-Translocating ATPases / chemistry
  • Mitochondrial Proton-Translocating ATPases / genetics
  • Molecular Sequence Data
  • Mutation
  • Neuromuscular Diseases / genetics*
  • Neuromuscular Diseases / pathology
  • Point Mutation


  • DNA, Mitochondrial
  • MT-ATP6 protein, human
  • Cytochromes b
  • Mitochondrial Proton-Translocating ATPases