Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) is a common inherited disease with a worldwide incidence of 1 in 3,500 male births. Recent molecular study on the DMD gene identified a 14-kb mRNA encoded by 79 exons distributed over 2.5 million bp of the X-chromosome. The protein named dystrophin contains 3,685 amino acids. Most of the genetic events (mutations) that inactivate the dystrophin gene have been shown to be deletions, with over 65% of patients exhibiting the loss of one or more of the exons at the genomic DNA level. The mechanism of the inactivation of the dystrophin gene in one third of patients with DMD/BMD is unknown.