Congenital myopathy with uniform type 1 fibers.

: Congenital myopathy with uniform type 1 fibers is a rare form of nonprogressive congenital neuromuscular disease. We report a 40 year old woman with proximal muscle weakness, waddling gait and decreased deep tendon reflexes. The serum creatine kinase level was decreased. Peripheral nerve conduction velocity as well as electrocardiogram and echocardiogram were normal. The electromyogram showed myopathic changes. A biopsy specimen from the left deltoid muscle revealed a uniformity of type 1 fibers. This is the first case of congenital myopathy with uniform type 1 fibers reported in Serbia.