A new approach for the identification of common point mutations within the dystrophin gene using MLPA

Between 70-75% of patients with Duchenne muscular dystrophy (DMD) have a large deletion or duplication of one or more exons in the dystrophin gene. The remaining patients are likely to have either a micro-deletion, micro-insertion or a point mutation. The Multiplex Ligation-dependent Probe Amplifi cation assay (MLPA) is quick and will detect all whole exonic deletions and duplications [1] however, point mutation analysis of the dystrophin gene remains diffi cult and time consuming due to the size of the gene. We have designed two MLPA probe mixes which are specifi c to 23 of the most common dystrophin gene point mutations (17% of all reported dystrophin point mutation cases). These point mutation probe mixes work simultaneously with the two commercial dystrophin MLPA probe mixes (P034/P035 MRC Holland), allowing both full dosage analysis and partial point mutation analysis in a two tube reaction. This method has been validated using nine positive controls.