We performed ultrastructural studies on nuclear abnormalities in biopsied muscles from
seven patients with EDMD, of three non-related families, and two sporadic cases. The
diagnosis was based on clinical data and molecular findings. We detected different degrees
of abnormalities in the sarcolemmal nuclei ranging from marked condensation of chromatin
to complete damage of nuclear components. Other nuclei in the same muscle cell very often
appeared normal. The extrusion of nuclear chromatin into sarcoplasm as a consequence of …