Multi-Omics Pipelines Transform Diagnosis of Mitochondrial Disease
Mitochondrial diseases affect over 300 genes and present with extreme clinical and genetic heterogeneity. This review describes how exome and whole-genome sequencing have largely replaced muscle biopsy as the first-line diagnostic approach, enabling minimally invasive genetic diagnosis from blood. For cases that remain unsolved by genomic sequencing alone, the authors make a compelling case for integrated multi-omics workflows combining transcriptomics, proteomics, and metabolomics to resolve variants of uncertain significance.
The original study
The genetics of mitochondrial disease: dissecting mitochondrial pathology using multi-omic pipelines.
- Authors
- Alston CL, Stenton SL, Hudson G, Prokisch H, Taylor RW
- Journal
- The Journal of pathology
- Type
- Journal Article, Research Support, Non-U.S. Gov't, Review
- PMID
- 33586140
Original abstract
Mitochondria play essential roles in numerous metabolic pathways including the synthesis of adenosine triphosphate through oxidative phosphorylation. Clinically, mitochondrial diseases occur when there is mitochondrial dysfunction - manifesting at any age and affecting any organ system; tissues with high energy requirements, such as muscle and the brain, are often affected. The clinical heterogeneity is parallel to the degree of genetic heterogeneity associated with mitochondrial dysfunction. Around 10% of human genes are predicted to have a mitochondrial function, and defects in over 300 genes are reported to cause mitochondrial disease. Some involve the mitochondrial genome (mtDNA), but the vast majority occur within the nuclear genome. Except for a few specific genetic defects, there remains no cure for mitochondrial diseases, which means that a genetic diagnosis is imperative for genetic counselling and the provision of reproductive options for at-risk families. Next-generation sequencing strategies, particularly exome and whole-genome sequencing, have revolutionised mitochondrial diagnostics such that the traditional muscle biopsy has largely been replaced with a minimally-invasive blood sample for an unbiased approach to genetic diagnosis. Where these genomic approaches have not identified a causative defect, or where there is insufficient support for pathogenicity, additional functional investigations are required. The application of supplementary 'omics' technologies, including transcriptomics, proteomics, and metabolomics, has the potential to greatly improve diagnostic strategies. This review aims to demonstrate that whilst a molecular diagnosis can be achieved for many cases through next-generation sequencing of blood DNA, the use of patient tissues and an integrated, multidisciplinary multi-omics approach is pivotal for the diagnosis of more challenging cases. Moreover, the analysis of clinically relevant tissues from affected individuals remains crucial for understanding the molecular mechanisms underlying mitochondrial pathology. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.