Mitochondrial DysfunctionDoes Clinical Treatment of Mitochondrial Dysfunction Impact Autism Spectrum Disorder (ASD)?

Inclusion Criteria:

1. Subject/legal representative is considered reliable and capable of adhering to the protocol (e.g., able to understand and complete diaries), visit schedule, and medication intake according to the judgment of the investigator.

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2. Subject has a formal diagnosis of autistic spectrum disorders (ASD). the ASD diagnosis will satisfy the DSM- V criteria for ASD, and will be broad-spectrum including both severe and milder cases.
3. All subjects will have either suspected mitochondrial dysfunction as assessed by clinical evaluation, mitochondrial dysfunction as defined by the presence of significant abnormalities in their buccal mitochondrial respiratory complex activities (i.e., with either respiratory complex I or complex IV deficiencies) or have significantly aberrant specific activity ratios. Subjects with significant deficiencies in either muscle or skin fibroblast respiratory activities will also be included in those cases if buccal mitochondrial respiratory enzyme activity testing has not been performed.

Exclusion Criteria:

1. Subject has any medical or psychiatric condition that, in the opinion of the investigator, could jeopardize or would compromise the subject's ability to participate in this study.
2. Subject has a medical condition that could be expected in the opinion of the investigator to interfere with drug absorption, distribution, metabolism, or excretion.
3. Subject is on a ketogenic or other specialized diet. If the subject was on a specialized diet in the past, they must be off the diet for ≥2 months prior to the Baseline Period.
4. Subject has an acute or sub-acutely progressive central nervous system disease.
5. Subject has major brain deformation or severe cognitive dysfunction.
6. Subjects with epilepsy needing to take anti-seizure medications will be excluded.