Ethical aspects of plans to combat Huntington's disease.

Consideration is given to some strategies to combat Huntington's disease in the absence of treatment to arrest its progress. Ethical issues for tests such as levodopa loading, to provoke symptoms prematurely in carriers of the gene, are compared with those associated with schemes for delaying the onset of disease. The major drawback of these designs is the uncertainty that prodromal symptoms may be extended unduly and the severity of deferred symptoms worsened. Some attention is also given to the possible use of post-onset plans to reduce illness severity and prolong survival. It is concluded that the characteristics of persons less prone to undesirable consequences of onset-delay should be adequately investigated before attempting to implement such schedules as a practical measure.