Inclusion Criteria:

* Male or female, ages ≥6 years at the time of signing the informed consent (and assent, if applicable).
* Diagnosis of FA, based on clinical phenotype and genotype (GAA expansion on both alleles or compound heterozygous), with onset of FA occurring at ≤25 years of age
* Confirmed left ventricular hypertrophy (LVH)
* Left ventricular ejection fraction ≥40%

Exclusion Criteria:

* Presence of other form(s) of CM contributing to heart failure (HF), clinically significant cardiac anatomic abnormality or congenital cardiac malformation, clinically significant coronary artery, uncorrected, hemodynamically significant primary structural valvular disease not due to CM
* Currently receiving intermittent or continuous intravenous (IV) inotrope infusion, presence of a ventricular assist device, or history of prior heart transplantation
* Contraindication to cMRI, participants <12 years of age who cannot complete the cMRI without sedation will instead undergo ECHOs and are exempt from this criterion.
* Prior organ transplantation
* Initiation of cardiac resynchronization therapy (CRT) within 6 months prior to screening.
* History of prior gene transfer or cell therapy.
* Poorly controlled diabetes (hemoglobin A1c ≥8%)
* Active hematologic or solid organ malignancy

Note: Other protocol defined Inclusion/Exclusion Criteria may apply.

Eligibility last updated 05/18/2026. Questions regarding updates should be directed to the study team contact.