AUTOSOMAL-DOMINANT HYALINE BODY MYOPATHY PRESENTING AS SCAPULOPERONEAL SYNDROME - CLINICAL-FEATURES AND MUSCLE PATHOLOGY

Hyaline bodies are rare subsarcolemmal aggregates in type 1 fibers of the skeletal muscle, stain pale pink with hematoxylin-eosin and pale g reen with the modified Gomori trichrome, and lack reactivity for glyco gen and oxidative enzymes. We report clinical findings of autosomal-do minant hyaline body myopathy in seven members in four generations and muscle biopsy findings in two of them. Slowly progressive muscle weakn ess and atrophy developed with scapuloperoneal distribution; age at on set was from the first to the fifth decade. Muscle biopsy showed subsa rcolemmal hyaline bodies in approximately 20% of type 1 fibers. Hyalin e bodies showed myofibrillar ATPase activity after acid pre-incubation . Immunohistochemically, they stained intensely with myosin heavy chai n (slow), but not with myosin heavy chain (fast). Ultrastructurally, t hey consisted of granules sometimes in linear array, filaments, and am orphous materials. These findings suggest that hyaline bodies may be p roducts of degeneration of myosin heavy chain (slow).