From History to Action

Family history can be viewed as the first stop in the assessment of genetic risks for any individual. For many genetic disorders there will be no obvious signs of symptoms until significant medical problems surface, so family history may be the only way to identify individuals at risk. This in turn can lead to a program of surveillance and management to mitigate the effects of the condition. Although the gold standard is a three-generation pedigree, many patients will not have all of the relevant information at their fingertips at the time of a clinic visit, and eliciting a full pedigree can be time-consuming; nevertheless, a set of pointed questions can identify risk for some of the more common conditions for which genetic testing is available. These include disorders that lead to an increased risk of cancer, sudden death due to cardiac dysfunction, hyperlipidemia, adverse drug reactions, and others. Recognition of the major patterns of genetic transmission, i.e., dominant and recessive, autosomal and sex-linked can reveal individuals and family members at risk who may benefit from genetic testing. Genetic testing itself is a process, beginning with recognizing the most appropriate test, explaining the risks, benefits, and limitations of testing to the patient, selecting an appropriate laboratory, and organizing testing with the laboratory. In some cases, this may be done by a non-genetic specialist, whereas in others the complexity of ordering and interpreting tests warrants involvement of a genetics specialist. In either case, the clinician needs to be prepared to help interpret the results in light of the family history and clinical presentation and to support the patient in future management and decision-making. Genetic test results may also have implications for other family members, which also need to be factored into pre- and post-test counseling.