DYSF and autosomal recessive limb-girdle muscular dystrophy type 2B: Understanding the structures and molecular mechanisms of large multi-functional ferlin proteins will be an important step toward understanding and treating ferlin-associated diseases such as Limb-Girdle Muscular Dystrophy type-2B (dysferlin), auditory neuropathy (otoferlin), and perhaps in the treatment of metastatic tumors (myoferlin).