Dysferlin is a muscle-specific protein that is essential for normal muscle function and development (1). Mutations in the human dysferlin gene, DYSF, which maps to chromosome 2p13.3-p13.1, are associated with limb girdle muscular dystrophy-2B (LGMD-2B) and a related, adult-onset, distal dystrophy known as Miyoshi myopathy (MM) (1,2). Dysferlin localizes to the muscle fiber membrane, but is absent in MM and LGMD-2B muscle (1,3). Dysferlin is detected in 5-6 week embryos, when limbs begin to f