[Amyloidosis in muscular dystrophy].

Mutations in the gene encoding dysferlin (DYSF) cause limb-girdle muscular dystrophy 2B (LGMD2B) and Miyoshi myopathy (MM). We were able to examine eight patients suspected of LGMD2B clinically, histochemically. The genotype was determined in every case. We found sarcolemmal and interstitial amyloid deposits in four muscle sections. All of the mutations associated with amyloid were located in the N-terminal region of dysferlin, and dysferlin clearly proved to be a component of the amyloid deposits. Dysferlin-deficient muscular dystrophy is the first muscular dystrophy in which amyloidosis is involved. This fact must be considered in the process of developing therapeutic strategies. The influence of the amyloid deposits on the pathogenesis of the disease and the possible involvement of other organs in the progressive course are as yet unclear.