Natural History Study in Pediatric Patients With MYBPC3 Mutation-associated Cardiomyopathy

Retrospective Who May Qualify: - Data is available for patient \<18 years of age. Patients must be \<18 years of age at enrollment or at time of death. - Documented results of genotyping showing the presence of at least one pathogenic or likely pathogenic MYBPC3 mutation (heterozygous, homozygous, or compound heterozygous). Who Should NOT Join This Trial: - Patient received cardiac transplantation or died \>10 years before study initiation. For homozygous or biallelic infants, data may be collected beyond this 10-year period. Prospective Who May Qualify: For Infants: - Infants who are homozygous or compound heterozygous for the known pathogenic truncating MYBPC3 mutations are eligible. For all other participants: - Age \<18 at entry into the prospective study. - Documented results of genotyping identifying at least one pathogenic or likely pathogenic MYBPC3 mutation (heterozygous, homozygous, or compound heterozygous). - Diagnosis of Cardiomyopathy (CM): HCM, DCM, RCM, mixed CM, or LVNC. Who Should NOT Join This Trial: - Concurrent participation in an interventional clinical trial unless approved by the sponsor. - Severe noncardiac disease anticipated to significantly reduce life expectancy. Always talk to your doctor about whether this trial is right for you.