Leder and co-workers deciphered the triple nucleotide code that designated the amino acids from which proteins were built. White blood cells were removed from the girl and the cells were inserted with normal copies of the defective gene and returned into the girls circulation. The faulty gene, CFTR, transfers salts across cell membranes, which causes mucus buildup in many tissues, particularly in the lungs. Infections lead to early death, usually by age 30. Cystic fibrosis currently has no effective treatment.
Gene therapy is one of the most exciting technologies for the future.
There are three techniques that researchers are working on. The defective cells are removed from the patient and replaced with the normal DNA before returning to the body. This therapy targets the blood cells because many genetic defects alter the functioning of one type of these cells or another. But since blood cells have limited life spans follow-up treatments are required. Future efforts will most likely target stem cells of the bone marrow.