Axonal filamentous spheroids associated with cardiomyopathy with "targetoid fibers". I. Clinical, histologic, and electron microscopic studies.

Abstract

A 13-year-old boy had cardiomyopathy, marked peripheral muscle atrophy and weakness, mild peripheral neuropathy, and mild cerebellar signs. At autopsy, axonal spheroids made up of aggregates of neurofilaments were found in the dorsal gray horns and dorsal columns of the spinal cord, in the tegmentum of the medulla, and in the dorsal spinal roots. A cardiomyopathy was present with targetlike (“targetoid”) fibers consisting ultrastructurally of electrondense material intermingled with fine fibrillary elements. Similar but less extensive changes were seen in the skeletal muscles. This case may represent a new disease entity resulting from an unknown metabolic defect that affects both the neural axons and the muscular tissue at a common basic level and produces abnormalities in the structure and physiology of the contractile elements of the affected tissue.