Multicore myopathy (MM) or Multi Minicore myopathy causes muscle fibre degeneration. Most cases of MM are inherited, but some are sporadic (the mutation only occurs in the affected person; it was not inherited and will not be passed onto children).
There are four types of MM:
MM affects both males and females. Close to half of MM cases are caused by a defective gene in one of two proteins: Selenprotein N1 (SEPN1) and Ryanodine receptor 1 (RYR1).
The main symptoms of MM are generalized weakness and muscle atrophy. Other symptoms depend on the type of MM. In some people, the disorder may remain stable for a long period of time, while some may experience progressive muscle weakness.
Treatment may include: