Becker muscular dystrophy: demonstration of the carrier status of a female by immunoblotting and immunostaining.

Becker muscular dystrophy (BMD) often results from in-frame mutations of the dystrophin gene, leading to the production of an altered-sized protein. We examined the expression of dystrophin in a BMD patient and in his asymptomatic mother by Western blot and immunofluorescence. The combination of these techniques allowed us to demonstrate the presence of two different dystrophins, normal-sized or reduced-sized in the muscular fibers of the asymptomatic carrier. This result emphasizes the value of dystrophin analysis for carrier detection and genetic counselling of families with Becker muscular dystrophy.