Benefits of Broad Genetic Testing Still Limited

Tuesday, June 17, 2008

ROCHESTER, Minn. — Five years ago, scientists finished mapping the complete human genetic code, but genetic assessment of disease risk remains in its infancy, according to the June issue of Mayo Clinic Women's HealthSource.

Scientists know that people share essentially the same genetic makeup, differing only by one-tenth of 1 percent. By studying that small variation, they hope to explain why one person is healthy and another sick and which treatments are best suited for each individual.

Scientists have identified "simple" genetic disorders caused by mutation of a single gene, for example, sickle cell anemia. Much more research is necessary on common diseases such as cancer, heart disease and diabetes, which are likely caused by a combination of genetic changes along with environmental influences.

Already, some private companies are providing DNA analysis to the public to assess disease risk. A few also offer genetic counseling and disease prevention and screening advice.

Experts caution that current tests don't identify all genetic variants that combine to predict vulnerability or resistance to a disease. And even then, an accurate test might not provide useful information. For example, most women have an estimated 10 percent lifetime risk of breast cancer. Some medical providers question the practicality of informing a woman her personal risk may be slightly higher. In most cases, screening and prevention options aren't changed.

Though not as exciting as new technology, a careful analysis of the extended family medical history can provide a form of genetic risk assessment that is just as useful as newer tests.

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Mayo Clinic Women's HealthSource is published monthly to help women enjoy healthier, more productive lives. Revenue from subscriptions is used to support medical research at Mayo Clinic. To subscribe, please call 800-876-8633, extension 9PK1, or visit www.bookstore.mayoclinic.com.

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