Gene Therapy for Cystic Fibrosis

Gene Therapy for Cystic Fibrosis

Modern molecular genetics has given hopes and heartaches to thousands of people around the world. These people are looking towards gene therapy for an answer to their questions. To some people such as NIH director Harold Varmus the answer is a better understanding of basic genetic research and to others the answer is a cure, a hope, that their lethal disease will someday be cured. This essay touches on the background of gene therapy for Cystic Fibrosis (CF), current social and ethical issues facing gene therapy for CF, and some thoughts on the importance of this controversial subject.

Gene therapy is the application of the technique where the defect-causing "bad" genes are replaced by correct "good" genes. The idea of gene therapy is to treat the disease by correcting the "bad" DNA (Deoxyribonucleic acid) rather than the current me thod of providing drugs, or proteins not produced by the defective gene. Gene therapy addresses the problem first hand by directly working with the genetic information causing the disease. From the book Shaping Genes, Dr. Darryl Macer says "It is like f ixing a hole in the bucket, rather than trying to mop up the leaking water." There are two kinds of gene therapy, somatic cell gene therapy and germline gene therapy.

Somatic cell gene therapy is where genes can be put into specific cells and areas of the body which are affected by the disease. All cellular DNA in our body is essentially the same because it was replicated from the same zygote (fertilized egg). Cel ls differentiate into their respective tissues depending upon which part of the total genome is used.

Germline gene therapy is where the correct "good" gene is inserted into the germline in place of the defective "bad" gene, and when reproduction occurs the gene will be passed on to the progeny. Inserting the "good" gene into the very early embryo sta ges of development allows for both germline and somatic cells to be corrected. Government has limited the research to only somatic cell gene therapy such as performed in Cystic Fibrosis research.

Cystic fibrosis is one of the most common lethal mutations in humans. The autosomal recessive allele is carried by 1/20 Caucasians, 1/400 couples will have children with the disease, and ¼ children will be afflicted. If untreated, 95% of affected ch ildren will die before age five (Bell, 1996).