Mitochondrial genome analysis of primary open angle glaucoma patients

PLoS One. 2013 Aug 5;8(8):e70760. doi: 10.1371/journal.pone.0070760. Print 2013.

Abstract

Primary open angle glaucoma (POAG) is a multi-factorial optic disc neuropathy characterized by accelerating damage of the retinal ganglion cells and atrophy of the optic nerve head. The vulnerability of the optic nerve damage leading to POAG has been postulated to result from oxidative stress and mitochondrial dysfunction. In this study, we investigated the possible involvement of the mitochondrial genomic variants in 101 patients and 71 controls by direct sequencing of the entire mitochondrial genome. The number of variable positions in the mtDNA with respect to the revised Cambridge Reference Sequence (rCRS), have been designated "Segregating Sites". The segregating sites present only in the patients or controls have been designated "Unique Segregating Sites (USS)". The population mutation rate (θ = 4Neμ) as estimated by Watterson's θ (θw), considering only the USS, was significantly higher among the patients (p = 9.8 × 10(-15)) compared to controls. The difference in θw and the number of USS were more pronounced when restricted to the coding region (p<1.31 × 10(-21) and p = 0.006607, respectively). Further analysis of the region revealed non-synonymous variations were significantly higher in Complex I among the patients (p = 0.0053). Similar trends were retained when USS was considered only within complex I (frequency 0.49 vs 0.31 with p<0.0001 and mutation rate p-value <1.49×10(-43)) and ND5 within its gene cluster (frequency 0.47 vs 0.23 with p<0.0001 and mutation rate p-value <4.42×10(-47)). ND5 is involved in the proton pumping mechanism. Incidentally, glaucomatous trabecular meshwork cells have been reported to be more sensitive to inhibition of complex I activity. Thus mutations in ND5, expected to inhibit complex I activity, could lead to generation of oxidative stress and favor glaucomatous condition.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Case-Control Studies
  • DNA Mutational Analysis
  • DNA, Mitochondrial / genetics
  • Electron Transport Complex I / genetics*
  • Gene Frequency
  • Genetic Association Studies
  • Genetic Predisposition to Disease
  • Genome, Mitochondrial*
  • Glaucoma, Open-Angle / genetics*
  • Haplotypes
  • Humans
  • Locus Control Region
  • Mitochondrial Proteins / genetics*
  • Multigene Family
  • Oxidative Stress
  • Polymorphism, Single Nucleotide
  • RNA, Ribosomal / genetics
  • RNA, Transfer, Leu / genetics

Substances

  • DNA, Mitochondrial
  • Mitochondrial Proteins
  • RNA, Ribosomal
  • RNA, Transfer, Leu
  • RNA, ribosomal, 12S
  • MT-ND5 protein, human
  • Electron Transport Complex I

Grants and funding

This study was supported by grants SIP-007, MLP-0016 and NWP 004 from the Council of Scientific and Industrial Research (CSIR), India. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.