DNA: Oracle or Nemesis?

NEW YORK: Throughout history, shamans and soothsayers, wizards and witches have tried to read and tame the future. Today, geneticists have joined the prediction business. If scientists can decode the genetic code and read the instructions, so the argument goes, they will find the key to human ailments and predict our predispositions.

Based on research, biotechnology companies have invested in sequencing technologies and developed predictive tests to identify those who are asymptomatic, but genetically predisposed to a growing number of genetic diseases and more common disorders such as certain types of cancer. Some scientists, indeed, are convinced that genetic tests will eventually help predict behavioral tendencies and personality traits – including predispositions to mental illness, homosexuality, addiction, even risk taking, timidity, and religiosity. In futuristic scenarios, they promise that genetic information will enhance control over both behavior and disease.

Genetic tests differ significantly from other clinical tests. They can be used to detect a condition in healthy people who have no reason to suspect they are at risk. They provide probabilistic information about a person’s predisposition to a disease that may or may not occur far in the future; they provide information that implicates not only the future of the individual but of family members as well.

There are among the many dangers that lurk here and many parties have less than a detached interest in this issue.

Some people hope that predictive information will open therapeutic possibilities. But even when genetic tests correctly predict that a person is at risk, there may be little or no benefit from that knowledge. Despite decades of promises, tests are available far in advance of therapies. On the other hand, once identified, a genetic predisposition to a debilitating disease for which there is no cure may immediately expose a person to stigmatization and discrimination.

A person “predisposed” to cancer, say, may have the biological qualities that heighten the odds of developing cancer, but many variables will influence the actual expression of the disease. In its social meaning, however, a predisposition is often defined as equivalent to having the disease. In a non-clinical context, individuals at risk in the future may be regarded as deserving differential treatment before it is known whether or not the disease will ever occur. Carrying the trait for a disorder, they can be labeled as “persons at risk” and deemed unsuited for normal activities.

Genetic labeling may create an underclass of individuals whose genes condemn them to discrimination. For this reason, many people who know they are at risk for a disease because of their family history have chosen not to be tested. Among people at risk for Huntington's Disease, for example, about 15% spurn taking the test that would provide definitive information.

Individuals considering genetic testing thus face difficult questions. Of what use is genetic information about a disease when there are no therapeutic options? Should a healthy woman diagnosed as susceptible to breast cancer undergo a prophylactic mastectomy? Should children and other family members who may also be at risk be informed? What are the implications of genetic screening for family planning? Eliminating genetic conditions ultimately depends on controlling reproduction. But policies of gene selection that may reduce the burden of disease border on the nightmare of eugenic controls.

While the patient may derive limited or no benefit from testing, others may have great interest in administering it. Predictive information allows various organizations to reduce costs or increase profits. The rising cost of medical care and insurance, for example, encourages insurance companies to try to weed out those who may have “unprofitable,” i.e., reimbursable, illnesses.

The need for profit encourages employers to give genetic tests to workers to discover who may be most productive, or who may be prone to illness that might lead to costly claims for compensation. Companies using toxic materials want to anticipate which workers may be genetically sensitive to toxic exposure. Schools, motor vehicle bureaus, adoption agencies, mortgage lenders, organ transplant registries all have a stake in information about genetic predispositions.

But above all, pressures from a biotechnology industry that stands to profit from the proliferation of tests drives the expansion of genetic testing. There are more than 450 research programs in America developing genetic tests. The commercial stakes are growing as it becomes possible to test for predisposition to common diseases such as breast cancer and heart disease where the potential market is immense.

Genetic prediction marks the intersection of scientific possibilities, economic interests, and consumer hopes and expectations. The ability to predict a growing number of complex and common diseases encourages testing, but also creates ethical dilemmas. The institutional interest in the predictive information from genetic tests conflicts with the rights and interests of individuals. Efforts to predict predisposition to behavior (as opposed to disease) will only compound these conflicts.

Today genetic tests yield probabilities and uncertain, inadequate information. But even if perfected, how should this information be used? Can we avoid the creation of a genetic underclass? Should we be seeking “genetic fixes” or ways to re-engineer the genes we pass on to our children? As we seek to control disease, can we afford to mandate controls over reproduction? Such questions will have increasing salience in light of the concerns about economic efficiency and cost containment that are shaping the efforts of today's shamans to read, assess, and tame the future in this, the age of biotechnology.