Carrier Diagnosis for Duchenne Muscular Dystrophy with Small Mutations in Dystrophin Gene

About one third of Duchenne muscular dystrophy (DMD) result from small mutations in the dystrophin gene, which could not be detectable by multiplex PCR or Southern blot analysis. In the families of DMD with small mutations, carrier diagnosis cannot be performed with conventional genetic strategies. We report here carrier diagnosis of 7 DMD families with small mutations in the dystrophin gene using direct sequencing of PCR products from genomic DNA. All mothers of the proband were diagnosed as heterozygous carrier, although 4 of them had no family history of DMD. The direct sequencing is an effective method for carrier diagnosis with small mutations in the dystrophin gene.