Tabriz University of Medical Sciences Medical Journal of Tabriz University of Medical Sciences 2783-2031 26 4 2005 01 20 Report of a Case with Kearns-Sayre Syndrome: A Kind of Mitochondrial Myopathy 76 78 EN khandaghi R SHAKOURI SK KIANMEHR A Journal Article 2013 07 13 A 14-year-old male presented with the chief complaint of bilateral progressive ptosis, which began approximately two years ago. He gradually felt weakness in his limbs. Initially, there were some differential diagnoses, such as spinal muscular atrophy (SMA) with bulbar involvement, neuromuscular junction problems, and some myopathies like myotonic with proximal predilection (proximal myotonic myopathy). With electrodiagnostic study, we ruled out these diagnoses. Kearns-Sayre syndrome (KSS) is a rare myopathy and usually presents with other systemic signs and symptoms, which should be considered as a differential diagnosis in all cases with myopathy and ptosis.