Observational Study of Natural History of BAG3 Gene Mutation-Associated Dilated Cardiomyopathy in Chinese Adults

This is a multicentre, prospective cohort study designed to elucidate the natural history of dilated cardiomyopathy (DCM) associated with specific gene mutations in Chinese patients. By establishing a cohort of patients with inherited cardiomyopathy, the study will collect comprehensive data, including demographic characteristics, disease history, clinical features, prior treatments, current treatment patterns, clinical outcomes, and patient-reported outcomes (PROs). The objective is to describe the disease profile, current diagnostic and therapeutic landscape, clinical progression, and prognosis of this specific patient population in China. The data generated will provide a foundational basis for deepening the understanding of disease progression, identifying unmet clinical needs, and exploring potential surrogate endpoints for future clinical trials in drug development. The study plans to enroll 10 eligible patients with BCL-2-associated athanogene 3 (BAG3)-associated inherited DCM from 3 research sites across China.

Inclusion Criteria: * Participants must meet all of the following criteria to be eligible for inclusion: 1. Age ≥18 years at screening, male or female; 2. Presence of a BAG3 pathogenic or likely pathogenic mutation interpreted according to the American College of Medical Genetics and Genomics (ACMG) guidelines; 3. Heart failure (HF) Stage B or C, New York Heart Association (NYHA) functional class I-III; 4. LVEF ≤50%. If LVEF is 45%-50% and the participant is classified as Stage B heart failure or NYHA Class I, N-terminal pro-B-type natriuretic peptide (NT-proBNP) must be ≥300 pg/mL. LVEF measurement must be based on echocardiography or cardiac magnetic resonance results within the past 12 months; 5. Willing and able to comply with all scheduled visits, laboratory tests, and other study procedures; 6. Capable of providing signed informed consent, including compliance with the requirements and restrictions listed in the informed consent form and this protocol. Exclusion Criteria: * Participants meeting any of the following criteria will be excluded: 1. Acute decompensated heart failure within 1 month prior to enrollment; 2. Any of the following within 3 months prior to screening: * Myocardial infarction * Cardiac surgical procedures (excluding pacemaker/implantable cardioverter defibrillator/cardiac resynchronization therapy implantation) * Implantable cardioverter defibrillator (ICD) implantation * Acute coronary syndrome * Hospitalization for cardiac arrhythmia 3. History of heart transplantation; 4. Estimated glomerular filtration rate (eGFR) \