DMD and Duchenne muscular dystrophy: Genetic diagnosis of DMD is most often achieved by PCR and multiplex ligation-dependent probe amplification (MLPA) of all 79 exons of DMD. Exonic sequence mutation analysis utilizes Sanger sequencing of PCR amplicons generated from each of the 79 exons, whereas MLPA uses probe hybridization and amplification to assay for deletions or duplications in the gene.