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 exonsin 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 Amplification assay (MLPA) is quick and will detect all whole exonic deletions and duplications [1] however, point mutation analysis of the dystrophin gene remains difficult and time consuming due to the size of the gene. We have designed two MLPA probe mixes which are specific 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.