Rapid identification of a novel complex I MT-ND2 m.10134C>A mutation in a Leigh syndrome patient

Authors

David K. Miller, University of Queensland
Minal J. Menezes, Children’s Hospital at Westmead, Sydney, New South Wales, Australia
Cas Simons, University of Queensland
Lisa G. Riley, Children’s Hospital at Westmead, Sydney, New South Wales, Australia
Sandra T. Cooper, Children’s Hospital at Westmead, Sydney, New South Wales, Australia
Sean M. Grimmond, University of QueenslandFollow
David R. Thorburn, University of Melbourne
John Christodoulou, University of Sydney
Ryan J. Taft, George Washington UniversityFollow

Document Type

Journal Article

Publication Date

8-12-2014

Journal

PLoS ONE

Volume

9

Issue

8

Inclusive Pages

Article number e104879

DOI

10.1371/journal.pone.0104879

Keywords

DNA, Mitochondrial--genetics; Electron Transport Complex I--genetics; Leigh Disease--genetics; Mutation, Missense

Abstract

Leigh syndrome (LS) is a rare progressive multi-system neurodegenerative disorder, the genetics of which is frequently difficult to resolve. Rapid determination of the genetic etiology of LS in a 5-year-old girl facilitated inclusion in Edison Pharmaceutical’s phase 2B clinical trial of EPI-743. SNP-arrays and high-coverage whole exome sequencing were performed on the proband, both parents and three unaffected siblings. Subsequent multi-tissue targeted high-depth mitochondrial sequencing was performed using custom long-range PCR amplicons. Tissue-specific mutant load was also assessed by qPCR. Complex I was interrogated by spectrophotometric enzyme assays and Western Blot. No putatively causal mutations were identified in nuclear-encoded genes. Analysis of low-coverage off-target mitochondrial reads revealed a previously unreported mitochondrial mutation in the proband in MT-ND3(m.10134C>A, p.Q26K), a Complex I mitochondrial gene previously associated with LS. Targeted investigations demonstrated that this mutation was 1% heteroplasmic in the mother’s blood and homoplasmic in the proband’s blood, fibroblasts, liver and muscle. Enzyme assays revealed decreased Complex I activity. The identification of this novel LS MT-ND3 variant, the genomics of which was accomplished in less than 3.5 weeks, indicates that rapid genomic approaches may prove useful in time-sensitive cases with an unresolved genetic diagnosis.

Comments

Reproduced with permission of PLoS ONE.

Creative Commons License

This work is licensed under a Creative Commons Attribution 3.0 License.

APA Citation

Miller, D.K., Menezes, M.J., Simons, C., Riley, L.G., Cooper, S.T., et al. (2014) Rapid Identification of a Novel Complex I MT-ND3 m.10134C>A Mutation in a Leigh Syndrome Patient. PLoS ONE 9(8): e104879.

Peer Reviewed

1

Open Access

1