Cell Therapy
All the cells of the body originated from a single cell - the zygote that was formed when sperm met egg - and all carry the same genetic information needed to construct the body. As the body grows some tissues (groups of cells) specialise to develop the liver, kidney, muscle etc. Although each cell still houses our entire genome most of these genes are "turned off" during development. Cells specialise and differentiate, structurally and functionally, for a particular purpose as only some genes are expressed.
Some cells remain undifferentiated. These Stem Cells remain totipotent or pluripotent and capable of developing into all or many kinds of specialised cells. If such undifferentiated cells could be delivered to a DMD patient then it might be possible to regenerate fully functional muscle fibres.
Normal muscles have small proportions of "satellite cells" or myoblasts, immature muscle cells that rest in a sort of suspended animation. There normal function is to come in and replace dead or damaged fibres. They can, however, be grown ex vivo to some extent, and theoretically they could then be transplanted from a healthy donor into a Duchenne patient. Clinical trials of myoblast transfer therapy have not so far proved to be successful but research is continuing to try to develop more effective methods.