Inherited and acquired mutations in the mitochondrial DNA can lead to several debilitating diseases, including blindness, neurodegeneration, and sarcopenia. Gene therapy can be a viable strategy to alleviate such diseases. We propose to identify variants of Cytochrome oxidase subunit 2 (COX2) and validate its utility in rescuing function in a model cell line derived from a multi-system disorder and COX2 deficient patient. Think of it as restoring the power plant that produces energy in a cell.