A. Marbini et al., CONGENITAL MYOPATHY WITH MOSAIC FIBERS AND INTERLACING SARCOMERES - ANEW STRUCTURAL MYOPATHY, Acta Neuropathologica, 96(6), 1998, pp. 643-650
A 44-year-old man presenting with dyspnoic attacks was found to be aff
ected with congenital myopathy, rigid spine, restrictive respiratory i
nsufficiency and cardiomyopathy. Muscle biopsy showed type 1 fiber pre
dominance (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. Ultrastructu
ral examination demonstrated bands of myofibrils at right angles or sk
ew to the remaining myofibrils transversing the fibers. Myofibrillar d
isarray was always associated with loss of the Z-discs and actin filam
ents, and often with aggregation of mitochondria. The muscle biopsy fi
ndings in this patient suggest a new entity of congenital myopathy wit
h clinical features of rigid spine, cardiomyopathy and restrictive res
piratory insufficiency, characterized by peculiar abnormalities of ATP
ase staining in a mosaic pattern and, ultrastructurally, by zones of d
isorientation of the sarcomeres.