The dramatic increases in the knowledge of the molecular and genetic basis of various diseases combined with advances in technology have resulted in novel molecular therapies for these diseases. Gene therapy, in utero or adults, which involves the transfer of genetic material to target cells via viral or non-viral vectors to produce a therapeutic effect, is a promising approach for treatment of a variety of diseases as hearing loss, paranasal sinus disease, recurrent respiratory papillomatosis, head and neck cancer, maxillofacial injuries and cleft palate.