Rett syndrome is a severe neurodevelopmental disorder that primarily affects female children. Rett syndrome is characterized by significant elevation in blood markers of oxidative stress. EPI-743 is a novel therapeutic with demonstrated efficacy and safety in the treatment of disorders characterized by oxidative stress. The purpose of this study is to examine the safety and efficacy of EPI-743 in a population of children with Rett syndrome.

Inclusion Criteria:

• Diagnosis of Rett syndrome with disease stage 1-2
• Abnormality of at least two disease biomarker levels
• Confirmed MeCP2 mutation
• Patient or patient's guardian able to consent and comply with protocol requirements
• Abstention from use of Coenzyme Q10, vitamin E and Idebenone two weeks prior to enrollment into the study

Exclusion Criteria:

• Any condition, which in the opinion of the investigator could compromise the subject's safety or adherence to treatment with EPI-743.
• Clinically significant allergy or hypersensitivity to EPI-743 or to any of the excipients of with EPI-743 (eg., sesame oil).
• Clinically significant allergy or hypersensitivity to Vitamin E
• Lack of confirmation of MeCP2 mutation
• Clinical history of bleeding or abnormal baseline PT/PTT
• Diagnosis of any other concurrent inborn error of metabolism
• Hepatic insufficiency with LFTs greater than 3 times upper limit of normal
• Renal insufficiency requiring dialysis
• End stage cardiac failure
• Fat malabsorption syndromes precluding drug absorption