| Nature and Purpose of the Testing |
Purpose of seeking the information. Does testing aim to diagnose an already existing set of symptoms? To assess an individual’s risk for future disease? To facilitate an intervention to prevent or treat disease? To facilitate a decision about pre-implantation genetic diagnosis or use of other reproductive technologies? The number of disorders tested for. Similarly, it would be rash to extrapolate from research into the impacts of learning about single conditions like Huntington’s, Alzheimer’s, and heredita0072y cancers (which patients will likely be familiar with, based on family history) to learning at once about the probabilities of developing multiple conditions. Character of the disorders (or traits) being investigated. It is one thing to test for what are regarded as diseases or disorders like cancer and another to test for predisposition to traits that are not so regarded, including conditions like autism spectrum disorder (which can be viewed as a difference rather than a disease) and outcomes like educational attainment (a recent target of genomic research (14)). |
| Characteristics of the Test Results |
The level of certainty associated with a test result. Most of the literature surveyed in this collection regards testing for completely or highly penetrant genes associated with a single disorder (such as Huntington’s, Alzheimer’s, or breast/ovarian cancer). But many of the results produced by the new sequencing technologies will yield findings that are of low- or mid-level penetrance or even of entirely unknown significance. As polygenic risk scores for complex disorders become more common, patients may receive information about risks for multiple disorders with limited predictive power. Insofar as managing probabilities and uncertainty is difficult for most of us, it would be a mistake to extrapolate too hastily, from the finding that, on average, negative impacts of testing for highly penetrant alleles are mild or transitory, to what will become the much more common case as exome or genome sequencing becomes the norm. Method of delivering the results. Were the test results conveyed by letter or email, on online web portal or electronic health record, or the person’s primary care physician (who may have little sophistication about genetics) or a genetic counselor or clinical geneticist? How much time was taken and how much context provided? Was the patient provided with educational materials or decision aids? |
| Context for the Testing |
Age at which testing occurs. Testing adults, children, newborns, fetuses, and embryos can raise different issues. When, for example, parents give consent for children or fetuses to be tested, more complicated relationship issues arise than when adults choose for themselves. Social context in which testing is done. Is the test being conducted in a clinical setting for a specific indication or is it part of a public health screening program? Is testing the result of concern about a family history of disease, another family member being identified as carrier (so-called cascade testing), or planned or actual pregnancy? Population in which testing is done. None of the pieces in this collection attends to whether different demographic groups are affected differently by the receipt of genomic information. There may turn out not to be significant differences, but one can’t know that from the literature surveyed here. |
| Methodologic Issues |
The impacts measured. Are the outcomes assessed readily identifiable symptoms (such as anxiety and depression) or are they more subtler symptoms (such as a decreased sense of agency)? Are objective outcomes assessed (for example, test performance) or are the measures entirely subjective? Are they measured in the short or long term (for example, six months or six years)? Method(s) used to investigate the impacts. Quantitative studies, traditional and interpretive qualitative studies, and mixed approaches all have different strengths and weaknesses. It is one thing for public health researchers to want to know average impacts across a population and another for clinician-researchers to want to know what the impact can be on individual patients. |
