Ethical considerations of biomarker use in neurodegenerative diseases--a case study of Alzheimer's disease.

A major issue in current Alzheimer research presents in a growing dysbalance between a swiftly advancing biological marker and diagnostic research field (including advances in genetic research towards genetic profiling), key aspects of which have already found their way into newly proposed diagnostic criteria and international clinical dementia guidelines, and still rather limited and stagnating therapeutic and preventive options for physicians and patients worldwide. While Alzheimer's disease (AD) to date can be diagnosed with high accuracy years ahead of the late stage clinical syndromal dementia manifestation supported by biomarker guided detection of AD-characteristic pathophysiological features, there are currently no approved preventive or disease-modifying therapies available and the existing approved symptomatic therapy options provide only modest effect sizes in already demented patients without affecting the overall course and progression of the chronically progressive and complex brain disease. This unsatisfactory situation brings along a number of important ethical issues that need to be addressed. We outline some of the relevant ethical implications mainly related to the patient's best interest as well as to the patient's autonomy in the specific context of medical, psychological and social consequences of predicting AD using multi-modal biological markers. Consent, disclosure, or failure to disclose, information from genetic and predictive biomarker results raises significant ethical concerns among IRBs, regulators and advocacy groups. With the swift advances in ever earlier detection, diagnosis and classification in AD, a worldwide debate on ethical issues and consensus processes to reach a common ethical framework is warranted to safely and responsibly bring the best possible diagnostic measures as early as possible to patients and to the health care system.