PDF(Pubmed)
Abstract：
Introduction: Rare disorders that are genetically and clinically heterogeneous, such as mitochondrial diseases (MDs), have a challenging diagnosis. Nuclear genes codify most proteins involved in mitochondrial biogenesis, despite all mitochondria having their own DNA. The development of next-generation sequencing (NGS) technologies has revolutionized the understanding of many genes involved in the pathogenesis of MDs. In this new genetic era, using the NGS approach, we aimed to identify the genetic etiology for a suspected MD in a cohort of 450 Portuguese patients. Methods: We examined 450 patients using a combined NGS strategy, starting with the analysis of a targeted mitochondrial panel of 213 nuclear genes, and then proceeding to analyze the whole mitochondrial DNA. Results and Discussion: In this study, we identified disease-related variants in 134 (30%) analyzed patients, 88 with nuclear DNA (nDNA) and 46 with mitochondrial DNA (mtDNA) variants, most of them being pediatric patients (66%), of which 77% were identified in nDNA and 23% in mtDNA. The molecular analysis of this cohort revealed 72 already described pathogenic and 20 novel, probably pathogenic, variants, as well as 62 variants of unknown significance. For this cohort of patients with suspected MDs, the use of a customized gene panel provided a molecular diagnosis in a timely and cost-effective manner. Patients who cannot be diagnosed after this initial approach will be further selected for whole-exome sequencing. Conclusion: As a national laboratory for the study and research of MDs, we demonstrated the power of NGS to achieve a molecular etiology, expanding the mutational spectrum and proposing accurate genetic counseling in this group of heterogeneous diseases without therapeutic options.
摘要：
简介：遗传和临床异质性的罕见疾病，如线粒体疾病（MD），有一个具有挑战性的诊断。核基因编码参与线粒体生物发生的大多数蛋白质，尽管所有线粒体都有自己的DNA.下一代测序（NGS）技术的发展彻底改变了对与MD发病机理有关的许多基因的理解。在这个新的基因时代,使用NGS方法，我们的目的是在一组450例葡萄牙患者中确定疑似MD的遗传病因.方法：我们使用联合NGS策略检查了450例患者，从分析213个核基因的靶向线粒体小组开始，然后分析整个线粒体DNA.结果与讨论：在这项研究中，我们在134例（30%）分析患者中发现了疾病相关变异，88具有核DNA（nDNA），46具有线粒体DNA（mtDNA）变体，其中大多数是儿科患者(66%)，其中77%在nDNA中鉴定，23%在mtDNA中鉴定。该队列的分子分析揭示了72个已经描述的致病性和20个新的，可能是致病的，变体,以及62个未知意义的变体。对于这群疑似MD的患者，定制基因小组的使用提供了及时和具有成本效益的分子诊断。在该初始方法之后不能被诊断的患者将被进一步选择用于全外显子组测序。结论：作为国家MD研究和研究实验室，我们证明了NGS实现分子病因的能力，扩大突变谱，并在这组没有治疗选择的异质性疾病中提出准确的遗传咨询。
