Individuals with a deficiency of the alpha 1-antitrypsin (AAT) protein are at risk for developing emphysema and liver damage. Researchers have developed a way to introduce normal AAT genes into muscle cells with the expectation that the AAT protein may be produced at normal levels. This study will evaluate the safety of the experimental gene transfer procedure in individuals with AAT deficiency. The study will also determine what dose may be required to achieve normal levels of AAT.