Microlesions and polymorphisms in the Duchenne/Becker muscular dystrophy gene.

One third of mutations responsible for Duchenne or Becker muscular dystrophy (DMD/BMD) represent point mutations or other small sequence alterations not readily detectable by Southern blot analysis or multiplex amplification. Here, we report results of a comprehensive point mutation search that yielded seven new sequence variations and one novel polymorphism. We also summarize known mutations, polymorphisms and other small nucleotide variations in the DMD gene. To date, 12 nonsense mutations, two missense mutations, six microdeletions and one microinsertion have been reported in the coding sequence and a further six mutations in splice sites all of which were made responsible for the disease. Twelve polymorphisms with frequencies suitable for diagnostic purposes have been detected. A further 28 differences from the published sequence of the coding sequence or the promoter region are described.