Appearance and localization of dystrophin in normal human fetal muscle.

We studied the localization of dystrophin in normal human fetal muscle by immunohistochemistry. Our results show the appearance of dystrophin at week 11 and a progressive organization of the protein along membrane in the following weeks of gestation. At week 22 almost all fibers show a clear membrane immunostaining. Concomitant analysis of muscle fiber-type composition reveals no correlation between progressive appearance of dystrophin and muscle fiber-type differentiation. Our findings suggest that synthesis and localization of dystrophin in developing human skeletal muscle is time-related and probably independent of neuronal influences.