Congenital myopathy with mosaic fibers and interlacing sarcomeres: a new structural myopathy.
A 44-year-old man presenting with dyspnoic attacks was found to be affected with congenital myopathy, rigid spine, restrictive respiratory insufficiency and cardiomyopathy. Muscle biopsy showed type 1 fiber predominance (65.7%) and hypotrophy, and characteristic changes in 43.9% of the type 1 fibers, consisting in alternating pale and dark staining on alkaline ATPase reacted sections in a mosaic pattern. Ultrastructural examination demonstrated bands of myofibrils at right angles or skew to the remaining myofibrils transversing the fibers. Myofibrillar disarray was always associated with loss of the Z-discs and actin filaments, and often with aggregation of mitochondria. The muscle biopsy findings in this patient suggest a new entity of congenital myopathy with clinical features of rigid spine, cardiomyopathy and restrictive respiratory insufficiency, characterized by peculiar abnormalities of ATPase staining in a mosaic pattern and, ultrastructurally, by zones of disorientation of the sarcomeres.
Marbini
A
A
University of Parma, Istituto di Neurologia, Italy.
Gemignani
F
F
Badiali
L
L
Bellanova
M F
MF
Margarito
F
F
D000328:Adult; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008854:Microscopy, Electron; D018485:Muscle Fibers, Skeletal / Q000378:metabolism / Q000473:pathology*; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology; D009135:Muscular Diseases / Q000151:congenital* / Q000378:metabolism / Q000473:pathology*; D012518:Sarcomeres / Q000378:metabolism / Q000473:pathology*; D013848:Thigh