Type III glycogenosis with multicore structures.

A case of an infantile type III glycogenosis (Forbes disease), confirmed by morphologic and biochemical studies, had light-microscopic, histochemical, and electron-microscopic evidence of multicore structures and type 1 fiber predominance with hypotrophy. This association is discussed with relation to the unusual clinical findings. The authors conclude that two distinct disease entities--Forbes disease and multicore myopathy--may coexist.