Molecular diagnosis in mitochondrial complex I deficiency using exome sequencing

Tobias B. Haack, Birgit Haberberger, Eva Maria Frisch, Thomas Wieland, Arcangela Iuso, Matteo Gorza, Valentina Strecker, Elisabeth Graf, Johannes A. Mayr, Ulrike Herberg, Julia B. Hennermann, Thomas Klopstock, Klaus A. Kuhn, Uwe Ahting, Wolfgang Sper, Ekkehard Wilichowski, Georg F. Hoffmann, Marketa Tesarova, Hana Hansikova, Jiri ZemanBarbara Plecko, Massimo Zeviani, Ilka Wittig, Tim M. Strom, Markus Schuelke, Peter Freisinger, Thomas Meitinger, Holger Prokisch

Research output: Contribution to journalArticle

Abstract

Background Next generation sequencing has become the core technology for gene discovery in rare inherited disorders. However, the interpretation of the numerous sequence variants identified remains challenging. We assessed the application of exome sequencing for diagnostics in complex I deficiency, a disease with vast genetic heterogeneity. Methods Ten unrelated individuals with complex I deficiency were selected for exome sequencing and sequential bioinformatic filtering. Cellular rescue experiments were performed to verify pathogenicity of novel disease alleles. Results The first filter criterion was 'Presence of known pathogenic complex I deficiency variants'. This revealed homozygous mutations in NDUFS3 and ACAD9 in two individuals. A second criterion was 'Presence of two novel potentially pathogenic variants in a structural gene of complex I', which discovered rare variants in NDUFS8 in two unrelated individuals and in NDUFB3 in a third. Expression of wild-type cDNA in mutant cell lines rescued complex I activity and assembly, thus providing a functional validation of their pathogenicity. Using the third criterion 'Presence of two potentially pathogenic variants in a gene encoding a mitochondrial protein', loss-of-function mutations in MTFMT were discovered in two patients. In three patients the molecular genetic correlate remained unclear and follow-up analysis is ongoing. Conclusion Appropriate in silico filtering of exome sequencing data, coupled with functional validation of new disease alleles, is effective in rapidly identifying disease-causative variants in known and new complex I associated disease genes.

Original languageEnglish
Pages (from-to)277-283
Number of pages7
JournalJournal of Medical Genetics
Volume49
Issue number4
DOIs
Publication statusPublished - Apr 2012

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)

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