Title : Next-Generation Sequencing in clinical diagnostics: Genetic testing, variant classification, and functional analysis
Next-generation sequencing (NGS) technology expanded in the last decades with significant improvements in the reliability, sequencing chemistry, pipeline analyses, data interpretation and costs. Such advances make the use of NGS feasible in clinical practice nowadays. This presentation describes the recent technological developments in NGS applied to the field of heterogeneous mitochondrial diseases showing lethal hypertrophic cardiomyopathy (HCM) and Leigh Syndrome (LS). A number of clinical applications are highlighted i.e., variant detection of autosomal recessive diseases based on DNA-sequencing, detection of splice variants based on RNA-sequencing, application for pre-implantation genetic diagnosis, downstream variant analysis by using functional model assays. In a recent study, we provided data of 3 families with pediatric HCM and LS, and multiple oxidative phosphorylation deficiencies (OXPHOS), but we identified the causative variant by exome-sequencing. Given the dual genetic heterogeneity of OXPHOS disorders with more than 1500 nuclear genes potentially involved, Whole Exome Sequencing (WES) is the best suitable unbiased approach for finding the underlying genetic cause. First, we started with an autosomal recessive disease model and in case of reported consanguinity i.e. one patient, we focused on homozygosity regions. Conclusive remarks, clinical and technical limitations, implications and ethical considerations that relate to NGS are provided in this presentation.
Audience Take Away:
• The audience will learn more about NGS in diagnostics as a first strategy to determine the genetic defect in pediatric mitochondrial diseases, variant classification, and functional assays.
• Improved understanding in dual genetic defects and clinical heterogeneous pediatric diseases.
• Implementing NGS in a clinical diagnostics area.
• Better understanding in variant classification and functional analysis. This NGS strategy improves the clinical diagnostic yield up to ~70% in most pediatric mitochondrial disease cases.