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Neuromuscul Disord. 2011 Mar;21(3):161-71. doi: 10.1016/j.nmd.2010.12.007. Epub 2011 Jan 20.

Myofibrillar myopathies.

Author information

1
Department of Neurology, Division of Child Neurology and Neuromuscular Disease Research Laboratory, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, MN, USA. Selcen.duygu@mayo.edu

Abstract

Myofibrillar myopathies represent a group of muscular dystrophies with a similar morphologic phenotype. They are characterized by a distinct pathologic pattern of myofibrillar dissolution associated with disintegration of the Z-disk, accumulation of myofibrillar degradation products, and ectopic expression of multiple proteins and sometimes congophilic material. The clinical features of myofibrillar myopathies are more variable. These include progressive muscle weakness, that often involves or begins in distal muscles but limb-girdle or scapuloperoneal distributions can also occur. Cardiomyopathy and peripheral neuropathy are frequent associated features. EMG of the affected muscles reveals myopathic motor unit potentials and abnormal irritability often with myotonic discharges. Rarely, neurogenic motor unit potentials or slow nerve conductions are present. The generic diagnosis of myofibrillar myopathies is based on muscle biopsy findings in frozen sections. To date, all myofibrillar myopathy mutations have been traced to Z-disk-associated proteins, namely, desmin, αB-crystallin, myotilin, ZASP, filamin C and Bag3. However, in the majority of the myofibrillar myopathy patients the disease gene awaits discovery.

PMID:
21256014
PMCID:
PMC3052736
DOI:
10.1016/j.nmd.2010.12.007
[Indexed for MEDLINE]
Free PMC Article

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