Farrokh Tirgari - Dept. of Pathology and Cancer Institute, Tehran University of Medical Sciences, Tehran, Iran
Fatemeh Mahjoub - Dept. of Pathology and Cancer Institute, Tehran University of Medical Sciences, Tehran, Iran
Zarrin Keyhani - Dept. of Pediatric Neurology, Tehran University of Medical Sciences, Tehran, Iran
Nargess Tabarzan - Tehran University of Medical Sciences, Tehran

Muscle tissue, skeletal muscle as well as cardiac muscle, is commonly affected in mitochondrial disorders. One explanation for this observation is that muscle tissue has a high-energy demandand therefore is more sensitive to a deficiency of mitochondrial energy production than some othertissues. In mitochondrial disorders, skeletal muscle tissue may be affected primarily by defective respiratory chain function or secondarily to peripheral neuropathy with neurogenic muscle atrophy.The clinical manifestations of mitochondrial myopathies are variable and include muscle weakness,exercise induced cramps and myalgia. Also, ptosis and progressive external ophtalmoplegia are typical but not obligate finding. Hereby we wanted to report a case of mitochondrial myopathy, diagnosed by histochemical and electron microscopic studies for the first time in Iran.Our case was a 12 year old girl who referred due to muscle weakness to our center which started an 4years ago. Later, she also developed ptosis. EMG studies were inconclusive and muscle biopsy revealedtypical red ragged fibers with special staining. By electron microscopy, typical mitochondrial changes were detected.

Mitochondrial Myopathies, Electron microscopy, Histocytochemistry