Heteroduplex analysis of the dystrophin gene: application to point mutation and carrier detection.

Approximately one-third of the Duchenne muscular dystrophy patients have undefined mutations in the dystrophin gene. For carrier and prenatal studies in families without detectable mutations, the indirect restriction fragment length polymorphism linkage approach is used. Using a multiplex amplification and heteroduplex analysis of dystrophin exons, we identified nonsense mutations in two DMD patients. Although the nonsense mutations are predicted to severely truncate the dystrophin protein, both patients presented with mild clinical courses of the disease. As a result of identifying the mutation in the affected boys, direct carrier studies by heteroduplex analysis were extended to other relatives. We conclude that the technique is not only ideal for mutation detection but is also useful for diagnostic testing.