Myo®brillar myopathy: clinical, morphological and genetic studies in 63 patients

The term myo®brillar myopathy (MFM) was proposed in 1996 as a non-committal term for a pathological pat-tern of myo®brillar dissolution associated with accumu-lation of myo®brillar degradation products and ectopic expression of multiple proteins that include desmin, aB-crystallin (aBC), dystrophin and congophilic amyloid material. Subsequent studies revealed dominant muta-tions in desmin and aBC in some MFM patients, and clinical differences between kinships. We here review the clinical, structural and genetic features of 63 unre-lated patients diagnosed as having MFM at the Mayo Clinic between 1977 and 2003. The age of onset was 54 6 16 years (mean 6 SD). Weakness was both proxi-mal and distal in 77 % and proximal only in 13%. Cardiomyopathy was diagnosed in 16%. Electro