A Natural History Study of RYR1-Related Disorders

* INCLUSION CRITERIA (CENTRALIZED ARM) 1. Stated willingness to comply with all study procedures, availability for the duration of the study, and submission of medical records to research team prior to screening. 2. Male or female, aged \>=7 years of age. 3. Genetically confirmed RYR1-related disorder, evidenced by pathogenic or likely pathogenic variants identified by CLIA testing (whole genome, exome, targeted, partial or full RYR1 sequencing) OR variant of uncertain significance with supporting clinical phenotype. 4. Agreement to adhere to Lifestyle Considerations throughout study duration. 5. Ability of subject to communicate their understanding of the purpose of the study, and willingness to provide assent and/or to sign a written informed consent document. 6. Resides in the United States. EXCLUSION CRITERIA (CENTRALIZED ARM) 1. Participation in an IND, IDE, or equivalent clinical study in the past six months 2. Severe disability or mobility issues (inability to walk 10 meters with or without assistance) 3. Requires mechanical ventilation or tracheotomy 4. Other neuromuscular diseases resulting in muscle weakness 5. Ongoing medical condition that is deemed by the Principal Investigator to interfere with the conduct or assessments of the study (e.g. active infection) or safety of the subject. INCLUSION CRITERIA (DE-CENTRALIZED ARM) 1. Stated willingness to comply with all study procedures, availability for the duration of the study, and submission of medical records to research team prior to screening. 2. Male or female, aged \> 7 years of age. 3. Genetically confirmed RYR1-related disorder, evidenced by pathogenic or likely pathogenic variants identified by CLIA testing (whole genome, exome, targeted, partial or full RYR1 sequencing) OR variant of uncertain significance with supporting clinical phenotype. 4. Ability of subject to communicate their understanding of the purpose of the study, and willingness to provide assent and/or sign a written informed consent document. 5. Resides in the United States EXCLUSION CRITERIA (DE-CENTRALIZED ARM) 1. Participation in an IND, IDE, or equivalent clinical study in the past six months 2. Other neuromuscular diseases resulting in muscle weakness 3. Ongoing medical condition that is deemed by the Principal Investigator to interfere with the conduct or assessments of the study (e.g. active infection) or safety of the subject