11.   Gene therapy is a relatively new arm of medicine in which copies of normal genes are used to replace or compensate for malfunctioning genes in the patient.

12.   Instead, gene therapy researchers use viruses to carry in copies of entire normal genes in an effort to replace defective genes.

13.   Inheriting a normal gene would save the individual from the disease.

14.   Several years ago, investigators discovered that an inactivated cold virus could add normal genes to cultured cells of patients with cystic fibrosis.

15.   The cells were grown in the laboratory and then returned to the mouse, where the normal gene could go to work.

16.   The normal gene controls the formation of adipocytes, or fat-storing cells.

17.   The scientists proved that they can safely transfer normal genes into the lungs of CF patients.

18.   The syndrome is brought on by an aberrant or mutated form of a normal gene.

19.   A control group of mice with normal genes were fed the same way.

20.   Adults who have certain mutant genes are far less likely to develop a form of leukemia than those with normal genes, according to a study released Monday.