ATR 1072 in Participants With PRKAG2 Syndrome

Inclusion Criteria: 1. Adults 18 to 65 years of age. 2. Pathogenic, likely pathogenic, or variant of uncertain significance (VUS) in PRKAG2 confirmed by genetic testing. 3. Clinical manifestations consistent with PRKAG2 Syndrome. 4. Able and willing to comply with study procedures. 5. Able and willing to undergo endomyocardial biopsy procedures (Part A) Exclusion Criteria: 1. Pregnancy or breastfeeding. 2. Significant hepatic, renal, hematologic, or cardiovascular abnormalities that may increase study risk. 3. NYHA Class IV heart failure or left ventricular ejection fraction \<45%. 4. Recent clinically significant cardiovascular events or procedures. 5. Prior treatment with prohibited investigational therapies or oligonucleotide therapies within protocol-defined washout periods. 6. Any condition that, in the investigator's