Unusual presentation as an adult onset painful myopathy in a Thai patient with Becker muscular dystrophy.

A Thai 37-years-old man presented with adult onset progressive proximal muscle weakness and generalized myalgia. Family history showed similar symptoms in several male relatives, compatible with X-linked recessive inheritance. Electromyography suggested myopathic process. Serum creatine kinase was highly elevated. Diagnosis of Becker muscular dystrophy (BMD) was confirmed by genetic testing. His symptoms responded well to steroid treatment. This report is of the first Thai patient with atypical presentation of BMD.