Letting the genome out of the bottle--will we get our wish?

n engl j med 358;2 www.nejm.org january 10, 2008 105 single-nucleotide polymorphisms (SNPs). His children, who were concerned about his health, spent $1,000 to give him the analysis as a holiday gift. The test report states that his genomic profile is consistent with an increased risk of both heart disease and diabetes, and because the company that performed the analysis stated that the test was “not a clinical service to be used as the basis for making medical decisions,” he is in the office for some “medical direction.” What should you do? This year has seen a dizzying number of genomewide association studies demonstrating associations between novel gene variants or chromosomal loci and common diseases and phenotypes. These studies rely on microarrays that can assess 300,000 or more SNPs in each DNA sample; researchers use these microarrays to examine interpersonal differences in inherited genetic variability and to compare the prevalence of gene variants among patients who have a given disease with that among controls. Such studies have identified associations with many gene variants that were not previously suspected to be related to the phenotypes under consideration. The new technologies involved have been a boon to researchers who needed unbiased clues as to the causation of diseases that may be used to develop new therapeutic and preventive interventions. The test undergone by the patient described above is one of the products of this new knowledge. As of November 2007, two companies have made available direct-to-consumer “personal genome services” (www.23andme. com) or “gene profiles” (www. decodeme.com) that rely on the same arrays of 500,000 to 1 million SNPs used in genomewide association studies. A third company (www.navigenics.com) has announced that it will offer similar services later this year. Essentially, a client sends a DNA sample to one of these firms, which analyzes the sample by means of SNP array; the data are stored in an online private account, the results are compared with allele– phenotype databases maintained and updated by the company, and the customer receives a readout of his or her levels of risk for specific conditions. But such premature attempts Letting the Genome out of the Bottle — Will We Get Our Wish?