Utility of array CGH in molecular diagnosis of mitochondrial disorders

Array comparative genomic hybridization (aCGH) is a powerful clinical diagnostic tool that can be used to evaluate copy number changes in the genome. Targeted aCGH provides a much higher resolution in targeted gene regions to detect copy number changes within single gene or single exon. A custom-designed oligonucleotide aCGH platform (MitoMet(®)) has been developed to provide tiled coverage of the entire 16.6-kb mitochondrial genome and high-density coverage of a set of nuclear genes associated with metabolic and mitochondrial related disorders, for quick evaluation of copy number changes in both genomes (1). The high-density probes in mitochondrial genome on the MitoMet(®) array allow estimation of mtDNA deletion breakpoints and deletion heteroplasmy (2). This technology is particularly useful as a complementary diagnostic test to detect large deletions in genes related to mitochondrial disorders.