Next‐generation sequencing for mitochondrial disorders

Abstract

A great deal of our understanding of mitochondrial function has come from studies of inherited mitochondrial diseases, but still majority of the patients lack molecular diagnosis. Furthermore, effective treatments for mitochondrial disorders do not exist. Development of therapies has been complicated by the fact that the diseases are extremely heterogeneous, and collecting large enough cohorts of similarly affected individuals to assess new therapies properly has been difficult. Next-generation sequencing technologies have in the last few years been shown to be an effective method for the genetic diagnosis of inherited mitochondrial diseases. Here we review the strategies and findings from studies applying next-generation sequencing methods for the genetic diagnosis of mitochondrial disorders. Detailed knowledge of molecular causes also enables collection of homogenous cohorts of patients for therapy trials, and therefore boosts development of intervention.

Leigh syndrome: One disorder, more than 75 monogenic causes

“…Whole genome sequencing can detect mutations in nuclear and mtDNA genes, but is less widely available than exome sequencing. Each of these approaches has specific advantages and disadvantages, 95,96 but in our experience they can enable molecular diagnosis of LS in >60% of patients with a stringent LS diagnosis, as defined by the original criteria of Rahman et al 2 …”

Identification of causative mutations in patients with Leigh syndrome and MERRF by mitochondrial DNA-targeted next-generation sequencing

“…In this study, we applied mtDNA-targeted NGS to identify genetic causes of the 2 studied diseases. NGS technology has been recently introduced in mtDNA testing for mitochondrial diseases [28][29][30]. The application of NGS may reduce the testing cost and time, with high fidelity.…”

“…Whole-mtDNA sequencing is usually performed by polymerase chain reaction (PCR) amplification of mtDNA with 46 fragments, with subsequent Sanger sequencing using a mitoSEQr resequencing system (Life Technology, Grand Island, NY, USA). Next-generation sequencing (NGS) technology, which has revolutionized the field of molecular biology, has recently been applied in the diagnosis of mitochondrial diseases [28,29]. The NGS technique is now recognized to reduce sequencing cost and analysis time, with high coverage and fidelity, thereby enabling the decoding of a number of human mitochondrial diseases.…”

Mitochondrial disease and the heart

“…Since mtDNA is highly polymorphic, a mutation can be considered pathogenic when segregates with the phenotype in affected families, it is absent in healthy controls and it has been potentially associated with a pathogenetic mechanism by molecular modelling or functional studies 52. Some preliminary experience shows that exome sequencing enhances the ability to identify potential nuclear gene mutations in patients with biochemically defined defects affecting multiple mitochondrial respiratory chain complexes 53 54.…”