Intra-myonuclear inclusions are diagnostic of oculopharyngeal muscular dystrophy

Abstract

ABSTRACTThe pathologies of oculopharyngeal muscular dystrophy (OPMD) and oculopharyngodistal myopathy (OPDM) are indistinguishable. We found that p62-positive intra-nuclear inclusions (INIs) in myonuclei (myo-INIs) were significantly more frequent in OPMD (11.4 ± 4.1%, range 5.0– 17.5%) than in OPDM and other rimmed vacuolar myopathies (RVMs) (1–2% on average, range 0.0–3.5%, p<0.0001). In contrast, INIs in nonmuscle cells (nonmuscle-INIs) were present in OPDM, but absent in other RVMs, including OPMD. These results indicate that OPMD can be differentiated from OPDM and other RVMs by the frequent presence of myo-INIs (≥5%) and the absence of nonmuscle-INIs in muscle pathology.