Misinterpretation of TPMT by a DTC genetic testing company.

23andme has suspended marketing of health-related reports due to US Food and Drug Administration approval violations. This has fostered discussions on the actual risks associated with consumer use of these reports. In the case described below, rare genotypes for the gene encoding thiopurine methyltransferase (TPMT) were misinterpreted by a direct-to-consumer (DTC) company, and risk calculations for breast cancer were offered when accuracy was not possible from the available information. Politics aside, these examples illustrate risks associated with DTC genetic testing without professional interpretation.