Genetics offers real opportunities for public health actors. Increased understanding of genetics will illuminate some of the factors that affect disease and, in many cases, will lead to more effective treatments. The recognition that phenylketonuria was caused by a metabolic defect that led to the accumulation of toxic levels of phenylalanine, an elevation that could largely be averted by adopting a low-phenylalanine diet, is an early example. Some cases of what was thought to be Sudden Infant Death Syndrome, a diagnosis (...) used when no etiology is known, now appear to have been caused by metabolic defects in fatty acid oxidation and sodium channel defects. One of the tasks that has already been undertaken by the public health sector is to ensure that genomic information is incorporated into clinical care when the robusmess of findings and their clinical utility have been well defined. (shrink)