P.349 - Myofibrillar myopathies with autophagic vacuoles: Report of a case series

Abstract

The presence of autophagic vacuoles containing lysosomal, autophagosomal and sarcolemmal membrane components depicts autophagic vacuolar myopathies as a spectrum of disorders unified by distinctive myopathologic features. While not being classified as autophagic vacuolar myopathies, also muscle disorders including myopathies with rimmed vacuoles, inclusion body myopathies and myofibrillar myopathies (MFM) have autophagic pathology. Here, we present the diagnostic algorithm which led us to the diagnosis of MFM in four unrelated patients with autophagic vacuolar myopathies. Patient 1 is a 39-year-old male, that came to our attention at the age of 35 for hyperCKemia (5× normal value) and a mild exercise intolerance; his clinical conditions have worsened in the last years of follow up, with the appearance of a progressive limb girdle weakness resembling a LGMD-like phenotype. Patient 2 is a 74-year-old woman with a 7-year history of a progressive axial and pelvic girdle weakness, in association with a moderate increase of blood CK (4× normal value). Patients 3 and 4 are respectively 19-year-old and 37-year-old males that present an asymptomatic hyperckemia (5× normal value), without muscle weakness. None of them is affected by cardiomyopathy. Their family history is inconsistent for neuromuscular diseases. The ultrastructural studies of the muscle biopsies have showed myofibrillar myopathy features, including progressive myofibrillar degeneration commencing at the Z-disk, accumulation of degraded filamentous material and entrapment of dislocated membranous organelles in autophagic vacuoles.