Although highly controversial , leveraging recent findings from GWAS together with high-throughput SNP genotyping technology, a number of companies now offer commercially available tests that aim to calculate an individual’s genetic risk for between 20–40 common, complex diseases using genome-wide genotyping. The purchase of these tests is ultimately initiated by consumers without the obligatory involvement of a health care provider . Costs currently range from $100 to over $2,000 per individual depending on the specific test and the company from which the test is purchased. Neurological/neuropsychiatric disorders which are represented across testing panels for the major personal genetic testing companies include Alzheimer’s disease, multiple sclerosis, and amyotrophic lateral sclerosis.
This type of testing is hotly debated for the reasons cited above, as well as because of the small effect sizes of SNP variants identified from GWAS and the fact that these variants explain only a small fraction of the total genetic variance and only confer small increases in disease risk. Even so, personal genetic testing proponents argue that providing this type of information directly to consumers can empower them to take control of their health by improving their compliance with health screening practices and by making more healthful lifestyle choices (i.e., make efforts to modify their disease risk). On the other hand, critics are concerned that there is a lack of research on how best to present this type of risk information to individual consumers to ensure adequate understanding of the results , as well as on how individual consumers are likely to respond to their results. Researchers focused on the ethical, legal, and social implications of such testing have noted that it is an open question as to whether this type of susceptibility testing would lead consumers to (a) make positive health behavior changes in response to their results; or (b) adopt more fatalistic attitudes and/or experience high levels of anxiety in response to estimates of high risk; or perhaps worse yet, (c) be falsely reassured by inaccurate or incomplete estimates of low risk. This becomes particularly problematic in light of recent evidence calling into question the consistency and accuracy of the risk estimates provided . In fairness to genetic studies, however, it is important to emphasize that all clinical testing and health care guidance from physicians and other health care providers (e.g., routine blood chemistries) suffer from some degree of variability and inconsistency. Studies are ongoing, including our own Scripps Genomic Health Initiative (SGHI), to shed light on some of these issues, in particular the behavioral and psychological response to testing and genomic risk disclosure.