Mutational and susceptibility genetics are different clinical paradigms.

During the past 2 years there have been several consensus conferences on diagnostic testing for Alzheimer’s disease (AD), specifically related to the use of new genetic tests (Farrer et al., 1995; Relkin et al., 1996). Unfortunately there is an appearance of controversy between some of the published opinions and the empirical data (Saunders et al., 1996; Slooter et al., 1996). The clinical paradigm for AD has changed from “ruling out” a small list of reversible and treatment causes of dementia to “ruling in” the diagnosis of AD using adjunctive genetic tests with a high positive predictive value for some patients (Roses & Saunders, in press).