Primer

Printer Friendly YES

Many, if not most, human diseases have their roots in our genes. More than 4,000 diseases are suspected to stem from mutated genes inherited from one or both parents. As of April 2000, 1,792 individual genes had been linked to disease, including common disorders such as heart disease and many cancers. These discoveries hold promise for new treatments.

Genes as Disease Carriers
Genes come in pairs, with one copy inherited from each parent. Many genes come in a number of variant forms, known as alleles. A dominant allele prevails over a normal allele. A recessive allele becomes apparent only if its counterpart allele becomes inactivated or lost. For example, in cystic fibrosis, the altered gene that causes abnormal mucus production and disease is a recessive allele. A person who inherits one copy of the recessive allele does not develop the disease because the normal allele predominates. Such a person is a carrier, however, and has a 50 percent chance of passing the recessive allele to his or her descendants. When both parents are carriers, the chance is one in four that a child will inherit two of the recessive alleles, one from each parent, and so develop the disease.

Predictive Gene Tests
Once scientists have linked a gene to a disease, predictive gene tests can be developed and used to identify individuals who are at risk of getting the disease, even before any symptoms appear. The most widespread type of genetic testing, newborn screening, can detect abnormal or missing gene products that might indicate a birth defect. Carrier testing can be used to help couples learn if they carry-and thus risk passing to their children-a recessive allele for inherited disorders. Doctors use genetic tests to identify telltale DNA changes in cancer or precancerous cells. Such tests can be helpful in several areas. These include early detection (for example, familial adenomatous polyposis genes prompt close surveillance for colon cancer); diagnosis (different types of leukemia can be distinguished); prognosis (the product of a mutated p53 tumor-suppressor gene flags cancers that are likely to grow aggressively); and treatment (antibodies block a gene product that promotes the growth of breast cancer).

Predictive gene tests have been or are being developed for diseases such as Tay-Sachs disease, cystic fibrosis, amyotrophic lateral sclerosis (ALS, or Lou Gehrig's disease), Huntington's disease, some forms of Alzheimer's disease, catastrophically high cholesterol, and several types of inherited cancer.

Gene Therapy
The discovery of genes and gene markers will provide invaluable tools for improving disease prediction, diagnosis and treatment. By spotting a mutated gene (or its protein product) in cells, doctors may be able to detect disease years earlier than with clinical or symptom-based diagnostic techniques. If a gene product is found to protect against a particular disease, it might be possible to synthesize that protein and use it as a drug or to find a drug that will interact with the protein to treat the disease. Ultimately, it may be possible to thwart disease with gene therapy-inactivating the flawed gene or replacing it. In this type of therapy, a gene may itself be a drug.

Animal and Microorganism Gene Patents
Patents for genes from nonhuman animals already exist. These patented genes help to provide a basis for the study of human diseases and a correlation for the discovery of related genes in humans. Many animal oncogenes have been used to provide a link to specific cancers in humans. For example, the rat neu oncogene was the preview to the human Her-2 oncogene. The discovery of this rat oncogene and later the human counterpart enabled researchers to create diagnostic tests for cancer.

Genetic materials from microbes are also patentable and are valuable diagnostic tools for disease detection and identification. For example, the entire HIV genome has been sequenced and patented. Although many diagnostic tests employ proteins as reagents, the genetic material of pathogenic microorganisms is useful for recombinantly expressing pathogen-specific proteins as well as for use as a diagnostic tool at the genomic level.

Agricultural Innovations
Agricultural biotechnology is another area where patent protection has been and continues to be valuable. The development of disease-resistant varieties of cucumbers, squash, melons and pumpkins is a perfect example of how the patent system promotes dissemination of information for future research and development. Additionally, there are patents that cover production of mammalian proteins in plants and plant cells, that is, plant bioreactors and methods of making sterile plants by recombinant techniques. There are also patents that cover transgenic plants that exhibit salt resistance and increased tolerance to drought. With an ever-expanding human population, coupled with increasingly scarce agricultural resources, agricultural innovation is essential.

About advertising opportunities