Gene Therapy Update
Posted February 1, 1998
Geneticists know that mutated genes are to blame for nearly 4,000 disorders that afflict humans. Until relatively recently, there have been few clues as to where on
our complement of 23 pairs of chromosomes these mutated genes might reside. The Human Genome Project has provided information that has allowed many of these genes to be tracked to particular
chromosomes, and some even to exact locations on those chromosomes.
Now that we are learning how to locate the mutated genes and identify the altered proteins they produce, we can ask the burning question, "Can scientists learn how
to prevent or treat these disorders?"
To do this requires knowing which mutated gene causes the disorder, what protein this gene normally produces, and how the altered protein or gene can be fixed or replaced.
The toolbox for delivering genetic therapy is becoming filled with mechanisms for dealing individually with specific disorders. Delivery of agents to correct the mutations
may include viral or nonviral strategies. Among the viral delivery systems are retrovirus, adenovirus, herpes simplex, and adeno-associated virus. Altered DNA might also be encased in
a complex of lipoproteins that are not associated with specific cells or viruses. A host of individual therapies are in clinical trials for cancer, AIDS, and the nervous system. Scientists
are proposing gene vaccinations to prevent a wide variety of maladies from bacteria-borne diseases to genetic disorders such as heritable cancers.
Although the future looks bright, there have been many challenges. One challenge is proving the technologies will work. Another is convincing the public of the benefits.
In addition the bioethical questions continue to plague us. For example, some scientists think that genetic therapy should only be used on body cells, but never on eggs and sperm. These
questions are perplexing, but society may very well be forced into answering them in the near future.
References
"Making Gene Therapy Work," Scientific American, June 1997, pp. 95-123.
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