The dystrophin-deficiency phenotype varies from a severe Duchenne-type to the milder allelic form known as Becker muscular dystrophy (BMD), determined in part by the location of the mutation in relation to the actin and dystroglycan binding domains and, in particular, by the mutation's effect on the reading frame [7]. This evidence concerns the gene DMD and hyperinsulinemic hypoglycemia, familial, 4.