MT-ND5 Mutation Exhibits Highly Variable Neurological Manifestations at Low Mutant Load

Yi Shiau Ng, Nichola Z. Lax, Paul Maddison, Charlotte L. Alston, Emma L. Blakely, Philippa D. Hepplewhite, Gillian Riordan, Surita Meldau, Patrick F. Chinnery, Germaine Pierre, Efstathia Chronopoulou, Ailian Du, Imelda Hughes, Andrew A. Morris, Smaragda Kamakari, Georgia Chrousos, Richard J. Rodenburg, Christiaan G.J. Saris, Catherine Feeney, Steven A. HardyTakafumi Sakakibara, Akira Sudo, Yasushi Okazaki, Kei Murayama, Helen Mundy, Michael G. Hanna, Akira Ohtake, Andrew M. Schaefer, Mike P. Champion, Doug M. Turnbull, Robert W. Taylor, Robert D.S. Pitceathly, Robert McFarland, Gráinne S. Gorman

Research output: Contribution to journalArticlepeer-review

Abstract

Mutations in the m.13094T>C MT-ND5 gene have been previously described in three cases of Leigh Syndrome (LS). In this retrospective, international cohort study we identified 20 clinically affected individuals (13 families) and four asymptomatic carriers. Ten patients were deceased at the time of analysis (median age of death was 10 years (range: 5·4 months−37 years, IQR = 17·9 years). Nine patients manifested with LS, one with mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS), and one with Leber hereditary optic neuropathy. The remaining nine patients presented with either overlapping syndromes or isolated neurological symptoms. Mitochondrial respiratory chain activity analysis was normal in five out of ten muscle biopsies. We confirmed maternal inheritance in six families, and demonstrated marked variability in tissue segregation, and phenotypic expression at relatively low blood mutant loads. Neuropathological studies of two patients manifesting with LS/MELAS showed prominent capillary proliferation, microvacuolation and severe neuronal cell loss in the brainstem and cerebellum, with conspicuous absence of basal ganglia involvement. These findings suggest that whole mtDNA genome sequencing should be considered in patients with suspected mitochondrial disease presenting with complex neurological manifestations, which would identify over 300 known pathogenic variants including the m.13094T>C.

Original languageEnglish
Pages (from-to)86-93
Number of pages8
JournalEBioMedicine
Volume30
Early online date24 Feb 2018
DOIs
Publication statusPublished - Apr 2018

Keywords

  • Heteroplasmy
  • Lactic acidosis and stroke-like episodes (MELAS)
  • Leigh syndrome (LS)
  • Mitochondrial DNA
  • Mitochondrial encephalomyopathy
  • Neuropathology

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