Primary mitochondrial myopathies (PMMs) are a group of rare, often life-threatening disorders caused by genetic mutations either within the mitochondrial or nuclear DNA affecting the energy needs of skeletal muscles. PMMs may present at any age and patients who manifest these diseases early in life often experience severe symptoms.
PMM can vary from person to person, even within the same family, and can affect major muscle groups that are used for walking, climbing, lifting objects or other everyday activities, and maintaining posture. High energy tissues like our heart, brain, and muscle are most affected by mitochondrial disorders.
Patients with PMM report mild to chronic fatigue, muscle pain, cramps, and a lack of endurance. Functional muscle impairment is also evident in smaller muscle groups that control, for example, movements of the eyes and eyelids and alterations in other muscles of the face and neck, which can lead to difficulty with swallowing and, more rarely, slurred speech.
Patients with PMM often receive dietary and nutritional supplements and are prescribed physical therapy exercise regimens.
Currently, there are no approved drugs for treatment of PMMs.