Having a blood test that accurately identifies a
disease-causing mutation is just the first step toward wide-scale testing.
Before predictive gene tests become generally available, specialists and
society at large can come to grips with major technical, ethical, and
economic concerns. These issues need to be addressed in carefully
conducted research programs, and the answers are likely to be several
years in coming.
Scientists are working to develop tests that are simple,
cost-effective, and accurate. Tests need to be validated in broader
populations, establishing that cancer susceptibility is caused by the gene
mutation itself, not by other genetic or environmental factors shared by
high-risk families. By comparing the cancer-causing genes of more and more
people, researchers will be able to zero in on which of a gene's many
mutations are significant and thus arrive at reasonably accurate
predictions of disease risk.
The logistics of delivering a test to the thousands or millions of
people who might want it - even limiting it initially to those with a
strong family history - is daunting. Demand could quickly overwhelm the
current extremely limited facilities and personnel available for DNA
testing. Laboratories need to develop proficiency in these new techniques,
and to assure accuracy and quality control.
Genetic counselors are also in short supply. People contemplating gene
testing need information and guidance in order to make informed choices
and weather the psychological stresses. The demand created by widespread
testing would readily swamp the nation's approximately 1,200 genetic
counselors, and it is likely that the task of education and counseling
will fall to primary care physicians and nurses. Few primary health care
providers, however, have training in this area.
Public health costs are significant. In addition to the charges for the
tests themselves, there are the expenses of counseling and of followup
clinical screening and frequent monitoring. And prophylactic surgery costs
many thousands of dollars.
Finally, gene testing raises serious ethical issues, including
confidentiality and discrimination. NIH is sponsoring studies of ethical
issues generated by the genetics revolution, with the goal of supporting
regulations and legislation to protect people from discrimination. Some
states have passed legislation on health insurance discrimination and
privacy. And research is under way to develop protocols to make sure that
gene tests are never given without prior informed consent.
