A rare mitochondrial disease with characteristics of exclusive skeletal muscle involvement without clinical evidence of other organ involvement. Disease manifestations are progressive limb weakness, proximal limb muscle atrophy and eye muscle anomalies (e.g. ocular motility restriction, ptosis). Patients may present with lactic acidosis, diffuse myalgia and overall fatigability (particularly during/after physical activities), dysphagia and diminished deep tendon reflexes. [from
SNOMEDCT_US]