Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK.
NHS Highly Specialised Service for Rare Mitochondrial Disorders, Queen Square Centre for Neuromuscular Diseases, The National Hospital for Neurology and Neurosurgery, London, UK.
Expert Rev Mol Diagn. 2023 Jul-Dec;23(9):797-814. doi: 10.1080/14737159.2023.2241365. Epub 2023 Aug 29.
Primary mitochondrial diseases (PMDs) comprise a large and heterogeneous group of genetic diseases that result from pathogenic variants in either nuclear DNA (nDNA) or mitochondrial DNA (mtDNA). Widespread adoption of next-generation sequencing (NGS) has improved the efficiency and accuracy of mtDNA diagnoses; however, several challenges remain.
In this review, we briefly summarize the current state of the art in molecular diagnostics for mtDNA and consider the implications of improved whole genome sequencing (WGS), bioinformatic techniques, and the adoption of long-read sequencing, for PMD diagnostics.
We anticipate that the application of PCR-free WGS from blood DNA will increase in diagnostic laboratories, while for adults with myopathic presentations, WGS from muscle DNA may become more widespread. Improved bioinformatic strategies will enhance WGS data interrogation, with more accurate delineation of mtDNA and NUMTs (nuclear mitochondrial DNA segments) in WGS data, superior coverage uniformity, indirect measurement of mtDNA copy number, and more accurate interpretation of heteroplasmic large-scale rearrangements (LSRs). Separately, the adoption of diagnostic long-read sequencing could offer greater resolution of complex LSRs and the opportunity to phase heteroplasmic variants.
原发性线粒体疾病（PMD）是一组由核 DNA（nDNA）或线粒体 DNA（mtDNA）中的致病性变异引起的遗传疾病，具有很大的异质性。新一代测序（NGS）的广泛采用提高了 mtDNA 诊断的效率和准确性；然而，仍存在一些挑战。
在这篇综述中，我们简要总结了 mtDNA 分子诊断的最新技术状态，并考虑了全基因组测序（WGS）、生物信息学技术以及长读测序的采用对 PMD 诊断的影响。
我们预计，无 PCR 的血液 DNA WGS 将在诊断实验室中得到更多应用，而对于有肌病表现的成年人，肌肉 DNA 的 WGS 将更为普及。改进的生物信息学策略将增强 WGS 数据的研究，更准确地描绘 WGS 数据中的 mtDNA 和 NUMTs（核线粒体 DNA 片段），更好的覆盖均匀性，间接测量 mtDNA 拷贝数，并更准确地解释异质性大规模重排（LSR）。此外，诊断性长读测序的采用可以提供更复杂的 LSR 分辨率，并提供异质性变体的相位机会。
