Dictionary.net

A strain of mice arising from a spontaneous mutation (mdx) in inbred C57BL mice. This mutation is X chromosome-linked and produces viable homozygous animals that lack the muscle protein dystrophin, have high serum levels of muscle enzymes, and possess histological lesions similar to human muscular dystrophy. The histological features, linkage, and map position of mdx make these mice a worthy animal model of Duchenne muscular dystrophy.