A Study of SGT-212 Gene Therapy in Friedreich's Ataxia

Inclusion Criteria:

• Has history of FA symptom onset ≤25 years of age

• Has a clinical and genetic diagnosis of FA

• Has a staging score of ≥1 but <6 on the Friedreich's Ataxia Rating Scale (FARS)Functional Disability Staging Score

• Is willing to agree to the following rules for use of omaveloxolone (Skyclarys):

1. For a candidate who is currently taking omaveloxolone, has been on a stabledose for 12 weeks, expects to continue taking omaveloxolone at that dosethroughout the study, and is willing to stop taking omaveloxolone at thedirection of the Investigator or Sponsor's Medical Monitor if evidence oftransaminitis or synthetic liver dysfunction is detected during the study

2. For a candidate who is not actively taking omaveloxolone, at least 12 weekshave passed since the last dose and the candidate agrees not to resumeomaveloxolone during the 18-month period after SGT-212 infusion NOTE: The useof any other approved or investigational medicinal product for the treatment ofFA should be discussed with the study team.

Exclusion Criteria:

• Antibodies against adeno-associated virus serotype 9 (AAV9)

• Has a modified FARS (mFARS) score <20

• Has a body weight ≤25 kilogram (kg) or has body mass index (BMI) ≥33 kg/m^2

• Has a contraindication to endomyocardial biopsy (EMB) or cardiac catheterization

• Is unable to undergo cardiac and brain MRI with contrast, including hypersensitivityto gadolinium contrast agent, presence of a non-MRI-compatible cardiac pacemaker,presence of a non-MRI-compatible implantable cardiac defibrillator, or physicalcondition (e.g., contractures)

• Has uncontrolled diabetes as defined by a hemoglobin (Hb) A1c >9%

• Has participated in recent interventional clinical studies or received anyinvestigational therapy administered within 3 months or 5 half-lives (whichever islonger) prior to Screening

• Has received gene therapy at any time

• Has contraindications to receiving corticosteroids

• Has any contraindication to the surgical procedures involved with IDN infusion ofSGT-212

• Has any known cardiac disease not related to FA including known obstructive coronaryartery disease (CAD)

• Other Inclusion/Exclusion criteria to be applied as per protocol.