Experiments to repair defective genes in humans could begin within a year but will not raise fundamentally new ethical issues, according to an Office of Technology Assessment report yesterday.
"Gene therapy that does not lead to inherited change is quite similar to other medical treatments," said Rep. Albert Gore Jr. (D-Tenn.), chairman of the investigations and oversight panel of the House Science and Technology Committee.
The report noted concern about techniques that could alter genes in reproductive cells because such modifications would be passed to subsequent generations. It outlined technology involved in human gene therapy and social, ethical and regulatory issues facing government agencies.
Genetic defects can cause between 2,000 and 3,000 diseases, but only a few could be treated with current technology. The first therapies will try to repair an enzyme deficiency caused by a single defective gene in bone-marrow cells.
Some such cells would be removed and grown in the laboratory. A virus would carry the normal gene into bone-marrow cells, replacing the defective gene. Repaired cells would be returned to the patient to produce the missing enzyme.
Current techniques cannot repair multigene defects or changes in whole chromosomes.
These therapies differ from more controversial treatments affecting reproductive cells. Several groups have objected to reproductive-cell alterations that would become a permanent part of the human genetic legacy.
Because the technology could be used "as part of a coercive social program to 'engineer' humans who are smarter or stronger," the report said, such therapies should not proceed without public discussion.