Thoughts on the Prospect of Elective Comprehensive Genome Screening

By Phyllis Griffin Epps

On October 28, 2002, “Morning Edition”, a radio broadcast produced by National Public Radio, aired a segment on genetic testing.  The piece was a commentary on the narrator’s experiences as he had his entire genome scanned for every known genetic trait of interest.  Through use of a blood sample, the company, Sequenome, searched for genetic traits known to have a causal relationship to disease or to suggest a predisposition to a medical condition.  The “genome scan” was not performed as part of a diagnostic or therapeutic process.  It was, in effect, genetic testing for screening, rather than diagnostic, purposes.  The narrator exercised his opportunity to participate in what is likely to become a service available on demand.

 The prospect of genetic testing for screening purposes available “without a prescription” prompts several concerns, none of which are fatal to the concept.  The value of the information received depends on two things: the quality of the entity or facility performing the analysis and sufficient ability to accurately interpret and relay the results to the paying customer.  Both concerns are manifest in the controversy regarding regulation of genetic testing, whether offered as a clinical service by laboratories or as genetic test kits.

Currently, the validity of genetic testing marketed as a clinical laboratory subject to regulation.  The Food and Drug Administration (FDA) regulates genetic tests marketed as kits but has not asserted its jurisdiction over laboratory services.  Laboratories that offer genetic testing as a service must be certified in accordance with the Clinical Laboratory Improvement Amendments of 1988 (CLIA).  CLIA is administered through the Center for Medical Services, is a cooperative effort between government and academia to certify the quality of laboratories that perform services involving human medical tests.  CLIA regulates the quality of the process by which the testing is performed.  The validity or utility of the actual test, however, is not subject to regulation.  As with companies that perform paternity tests and similar services, the consumer who shops for a genome scan or other genetic testing must be vigilant in assessing the quality of the facilities.

Second, the validity of the results of screening one’s genome is necessarily limited by what is not yet known about the interactions between genes and the environment.  A fair interpretation of the output of a comprehensive genome scan must educate and disclose to the consumer about the qualifications of the results.  From Huntington’s Disease to heart disease, more and more is known of the relationship that can exist between a variation in the composition of a gene and the risk of an actual diagnosis of a particular condition in the future.  Scientists know less of the manner in which genes interact with each other across the genome.  As an oversimplified example, the existence of a genetic variation X and, elsewhere on the genome, variation Y, may together counteract and thereby lessen the influence of variations A, B, and C on the future health of the individual.

Still less is known of the effects of environment on the penetrance or expression of a genetic variation or combined existence of several variations.  Even within families, no two individuals will have the same history of diet, air quality, or other stimuli.  Without the ability to control for environment, biomedical researchers will make slow progress in solving all the mysteries of the genome.  The customer who is scanned for every known genetic trait associated with a disorder still will have only half of the story, if that much.

The validity and utility of the genetic testing to which the narrator was subject are not regulated.  Even where CLIA-certified laboratories are involved, the safety and effectiveness of genetic testing services are not assessed by any entity other than the laboratory or the marketplace.  Calls for regulation, by the FDA in particular, have met with resistance.  In 2000, the Secretary’s Advisory Committee on Genetic Testing recommended that the FDA be the federal agency primarily responsible for the regulation of all genetic tests and assert jurisdiction over both kits and clinical services involving genetic testing.  As of September of this year, the committee has stopped work and is undergoing an overhaul prompted by the current presidential administration.

Additional regulation would increase the time and money required to bring genetic testing to the marketplace.  Moreover, the FDA’s approval process is notorious for its slow pace and bureaucracy.  Despite the odd proposal to implement regulations through a voluntary process involving the FDA and CMS, no system of oversight has generated consensus.

The company that performs the scan has a professional interest in ensuring that the consumer is fully educated about the utility of the results.  The importance of education is not unrelated to the process of obtaining informed consent.  The customer must be made aware not only of what the scan will entail, but also the limits on the ability of the results to predict future health.  Only after such counseling can both the company and consumer be assured of full contractual agreement.  Nevertheless, buyers beware.

 The prospect of using knowledge about variations across the genome to predict future health is at once exciting and frightening.  The person who learns of a susceptibility or predisposition toward a condition like heart disease may adapt a lifestyle with a preventative effect.  Another person might enjoy a false sense of security after “testing negative” for the presence of a particular genotype, only to suffer from the condition in the future.  The proliferation of elective screening may alter reproductive, career, and other personal decisions, not unlike the scenario depicted in the surprisingly prescient movie Gattica.  Of course, attempts to cheat disease and death will always be subject to an infinite number of factors that no one individual can control (drunk drivers, war, and pestilence are only a few examples).  With adequate quality assurance and education about the meaning of the results, comprehensive screening of the genome ultimately may change the meaning of the phrase “planning for the future.”-

12/23/02