Evidence for a chronic axonal atrophy in oculopharyngeal "muscular dystrophy"

We report on morphometric investigations of peripheral nerves in a woman, who died at the age of 69, presenting the classical symptoms of oculopharyngeal muscular dystrophy (OPMD) and a typical family history with several members (males and females) affected over three generations. Evidence for chronic axonal atrophy was found in peripheral nerves and especially in oculomotor nerves with severe axon loss in endomysial nerve twigs of extraocular, laryngeal, and tongue muscles. Whereas limb muscles presented features of neurogenic atrophy, severe changes of "myopathic" type were evident in extrinsic eye muscles, laryngeal constrictor, tongue, and diaphragma. However, we interpreted these changes as neurogenic in origin in view of the severe denervation found in those muscles. Our findings suggest that OPMD is a disease of primary neurogenic origin rather than a primary myopathic disorder.