In clinical testing, an individual chooses to undergo genetic testing to know the outcome, whereas in a research setting, the individual may choose not to know the result of the test or the research protocol might specify that individual's test result not be divulged. Because of potential problems in interpreting the results, some would argue that blood testing for PD genes be carried out preferably under a research setting. If carried out under a clinical setting, the laboratory carrying out the test should preferably be accredited by the relevant authorities. A multidisciplinary team comprising a neurologist, a genetic counselor, a psychologist, nurse clinicians, and other support paramedical staff should be available before genetic testing can be undertaken. Interpretation of the tests should preferably be conducted by professionals who are appropriately qualified or have sufficient experience. Specifically, the limitations of testing should be clearly explained to the patients, including the potential for future denial of employment opportunities or medical, disability, or life insurance. A negative test may be uninformative, and not all abnormal results are diagnostic or useful. Based on current information, an abnormal test cannot accurately provide prognosis (such as rate of progression) in affected individuals nor exact age at onset of symptoms in asymptomatic subjects. Because DNA testing may have serious implications not only for the patient, but also for other family members, it should be performed only after very careful consideration of all potential factors. Because of the mostly adult-onset symptoms and the absence of preventive, neuroprotective, or disease-modifying strategies, skilled genetic counseling is essential for addressing the ethical, social, legal, and psychological issues associated with genetic testing. Psychological problems with predictive testing should be anticipated and properly managed. The lessons and experience with genetic testing in Huntington disease provide a useful framework and stepping stone for testing in PD.61- 63 These include confirmatory testing, predictive testing, asymptomatic testing for children, confidentiality, insurability, finances, employment, disability, and marriage.61 However, the technical and scientific issues with testing in PD are more complicated than in Huntington disease, and hence a common set of guidelines is not feasible. Prenatal testing or testing in asymptomatic children should be strongly discouraged. Cost-effect analysis is needed because screening may involve genes like parkin where more than 100 different mutations have been described.