The molecular study of mitochondrial diseases, essential for diagnosis, is special due to the dual genetic origin of these pathologies: mitochondrial DNA and nuclear DNA. Complete mtDNA sequencing still remains the first line diagnostic test followed if negative, by resequencing panels of several hundred mitochondrially-encoded nuclear genes. This strategy, with an initial entire mtDNA sequencing, is currently justified by the presence of nuclear mitochondrial DNA sequences (NUMTs) in the nuclear genome. We designed a resequencing panel combining the mtDNA and 135 nuclear genes which was evaluated compared to the performances of the standard mtDNA sequencing. Method validation was performed on the reading depth and reproducibility of the results. Thirty patients were analyzed by both methods. We were able to demonstrate that NUMTs did not impact the mtDNA sequencing quality, as the identified variants and mutant loads were identical with the reference mtDNA sequencing method. Reading depths were higher than the recommendations of the MitoDiag French diagnostic network, for the entire mtDNA for muscle and for 70% of the mtDNA for blood. These results highlight the usefulness of combining both mtDNA and mitochondrially nuclear-encoded genes and thus obtain more complete results and faster turnaround time for mitochondrial disease patients.
Keywords: ADN mitochondrial; ADN nucléaire; ADN nucléaire d’origine mitochondriale; ADNmt; ADNn; Ataxie et Rétinite Pigmentaire; HP; MELAS; MERRF; MM; Myoclonic Epilepsy with Ragged Red Fibers (épilepsie myoclonique avec fibres rouges déchiquetées); NARP; NGS; Neuropathie; acidose lactique et pseudo-accidents ischémiques cérébraux); encéphalopathie; genetic diagnosis; hétéroplasmie; inherited metabolic disorders; maladie mitochondriale; mitochondrial DNA; mitochondrial diseases; mitochondrial encephalopathy with lactic acidosis and stroke-like episodes (myopathie mitochondriale; nuMT; séquençage de nouvelle génération.