APOLIPOPROTEIN-E GENOTYPING IN ALZHEIMERS-DISEASE

Apolipoprotein E(APOE=gene; apoE=protein) is the first identified gene tic susceptibility factor for sporadic Alzheimer's disease (AD). The a pplication of APOE genotyping to the prediction and diagnosis of AD ha s been a source of controversy for the public and for clinicians and s cientists. These issues were explored by a 33 member working group in a two-day conference held in October, 1995, and sponsored by the Natio nal Institute on Aging, the Alzheimer's Association (USA), and other o rganisations. The group's conclusions are: The use of APOE genotyping to predict future risk of AD in symptom-free individuals is not recomm ended at this time. Insofar as patients with AD are more likely to hav e an APOE-epsilon 4 allele than are patients with other forms of demen tia or individuals without dementia, physicians may choose to use APOE genotyping as an adjunct to other diagnostic tests for AD. Since geno typing cannot provide certainty about the presence or absence of AD, i t should not be used as the sole diagnostic test. In deciding whether or not to carry out APOE genotyping for any purpose, physicians and pa tients should bear in mind that genotype disclosure can have adverse e ffects on insurability, employability, and the psychosocial status of patients and family members. Clinical and research applications of APO E genotyping must:be linked to adequate pre-test and post-test counsel ling, education, and psychosocial support. Research priorities include large-scale, prospective investigations of dementia incidence as a fu nction of APOE genotype, and the development of novel approaches to th e prevention and treatment of AD based on knowledge of the role in the disorder played by APOE and other factors.