Clinical information:  The patient was a 23 year-old woman who was referred for evaluation of muscle weakness and elevated creatine kinase (CK) level in serum. She was a college student.  She grew up in a farm and had a tendency to feel tire easily since childhood. She was unable to keep up with her peers in athletic events and heavy farm work. Weakness accompanied by a burning sensation in muscle often occurred shortly after she started to exercise and her symptoms improved with rest. Myalgia would occur after exercise.but there was no experience of tea-colored urine after exercise.  Her serum CK level was elevated to two to three times normal on several occasions. On neurologic examination, there was no definitive weakness, muscle wasting, or hypertrophy. An electromyogram (EMG) of her limb muscle was normal. Her thyroid profile was normal. There was no family history of muscle disease. A muscle biopsy was obtained from the vastus lateralis.

A.	B. MGT	C. ATPase	D. NADH-TR	E. SDH	F. EST	G. Oil red O
H. PAS	I. PASD	J. AD	K. PHOS	L. PHOS Control	M. Semithin	N.

What is your diagnosis? Discussion