A Natural History Study of RYR1-Related Disorders

Background: Congenital myopathies (CM) are genetic disorders that can cause decreased muscle tone and muscle weakness. Most CMs in the United States are related to the ryanodine receptor 1 (RYR1) gene. Researchers need more natural history data to learn about these CMs in children and adults. Objective: To learn more about the signs, symptoms, and course of RYR1-related disorders. Eligibility: People aged 7 years and older with an RYR1-related disorder. Design: Ambulatory participants will come to the Clinical Center and non-ambulatory participants will visit via telehealth. Visits will be once a year for 3 or 5 years. Clinical Center visits will take 2 to 3 days. All participants will undergo tests including: Photos and videos. These will be taken to document the participant s condition. Blood and urine tests. Activity Tracker. Participants will wear a device to record their activity. Questionnaires. Participants will answer questions about their health, pain, fatigue, stress, quality of life, and other topics. Participants who visit the Clinical Center will also undergo: Tests of heart and lung function. Motor skills and strength tests. Participants will walk, climb stairs, kneel, crawl, stand up, and perform other movements to test their strength and abilities. They will squeeze and pinch a handheld device to test their grip. Imaging scans. Skin biopsy. Adult participants may opt to have a sample of skin taken (one time only). Eye exam