 PAX3 mediates the transcription of c-Met and is responsible for the activation of MyoD expression—one of the functions of MyoD is to promote the regenerative ability of satellite cells (described below).PAX3 is generally expressed at its highest levels during embryonic development and is expressed at a lesser degree during the fetal stages; it is expressed in migrating hypaxial cells and dermomyotome cells, but is not expressed at all during the development of facial muscle.Mutations in Pax3 can cause a variety of complications including Waardenburg syndrome I and III as well as craniofacial-deafness-hand syndrome.