The mdx mouse, which carries a nonsense mutation in exon 23 of the dystrophin gene, has
been used as an animal model of Duchenne muscular dystrophy to evaluate cell or gene
replacement therapies. Despite the mdx mutation, which should preclude the synthesis of a
functional dystrophin protein, rare, naturally occurring dystrophin-positive fibres have been
observed in mdx muscle tissue. These dystrophin-positive fibres are thought to have arisen
from an exon-skipping mechanism, either somatic mutations or alternative splicing …