The purpose of this study is to provide participants who successfully completed the study titled "An Open-label, Safety Study for Previously Treated Vatiquinone (PTC743) Subjects With Inherited Mitochondrial Disease" with liquid Vatiquinone through an intermediate patient population expanded access protocol.

This expanded access protocol serves to make Vatiquinone accessible to subjects with inherited mitochondrial disease who previously participated in a Vatiquinone clinical trial at the Medical University of South Carolina (MUSC) who in the opinion of the investigator would benefit from continued access to liquid Vatiquinone.

Inclusion Criteria:

• Subjects with molecular genetic mitochondrial disease including Leigh syndrome, and Alpers syndrome.
• Completed participation in the study titled "An Open-label, Safety Study for Previously Treated Vatiquinone (PTC743) Subjects With Inherited Mitochondrial Disease"
• In the opinion of the clinical investigator, the continuation to receive Vatiquinone will be of benefit to the participants.
• Enrollment into a clinical trial to receive Vatiquinone is not possible

Exclusion Criteria:

• Current participation in any other interventional study
• Pregnant or currently breast feeding.