X-linked Duchenne muscular dystrophy in an unusual family with manifesting carriers.

We report a unique case of a 46-year-old female who had signs of Duchenne-like muscular dystrophy on clinical, electromyographic, and laboratory investigation. A brother, sister, maternal uncle, and her own son also had Duchenne type muscular dystrophy. Karyotype analysis in the proband showed both the X chromosomes to be morphologically normal. We discuss different hypothetical mechanisms to account for the family pedigree.