Natural History Study of Mitochondrial Myopathy

This natural history study follows people with mitochondrial myopathy — a genetic condition where the cells that power muscles don't work properly, causing weakness, fatigue, and exercise intolerance. The goal is to understand how the disease changes over time. The study also enrolls healthy volunteers for comparison. There is no experimental treatment involved. You may be eligible if: - You are any age (0–100 years) - You have a confirmed or suspected diagnosis of mitochondrial myopathy (based on genetics, lab tests, or clinical presentation) - You experience muscle weakness, exercise intolerance, or fatigue related to a mitochondrial condition - OR you are a healthy volunteer with no history of mitochondrial disease You may NOT be eligible if: - You are a fetus - You do not speak English - You are a study staff member or immediate family of one - (For healthy volunteers) You have a confirmed genetic mutation causing mitochondrial disease Talk to your doctor to see if this trial is right for you.