Disclosure of APOE genotype for risk of Alzheimer's disease.

BACKGROUND: The apolipoprotein E (APOE) genotype provides information on the risk of Alzheimer's disease, but the genotyping of patients and their family members has been discouraged. We examined the effect of genotype disclosure in a prospective, randomized, controlled trial. METHODS: We randomly assigned 162 asymptomatic adults who had a parent with Alzheimer's disease to receive the results of their own APOE genotyping (disclosure group) or not to receive such results (nondisclosure group). We measured symptoms of anxiety, depression, and test-related distress 6 weeks, 6 months, and 1 year after disclosure or nondisclosure. RESULTS: There were no significant differences between the two groups in changes in time-averaged measures of anxiety (4.5 in the disclosure group and 4.4 in the nondisclosure group, P=0.84), depression (8.8 and 8.7, respectively; P=0.98), or test-related distress (6.9 and 7.5, respectively; P=0.61). Secondary comparisons between the nondisclosure group and a disclosure subgroup of subjects carrying the APOE epsilon4 allele (which is associated with increased risk) also revealed no significant differences. However, the epsilon4-negative subgroup had a significantly lower level of test-related distress than did the epsilon4-positive subgroup (P=0.01). Subjects with clinically meaningful changes in psychological outcomes were distributed evenly among the nondisclosure group and the epsilon4-positive and epsilon4-negative subgroups. Baseline scores for anxiety and depression were strongly associated with post-disclosure scores of these measures (P<0.001 for both comparisons). CONCLUSIONS: The disclosure of APOE genotyping results to adult children of patients with Alzheimer's disease did not result in significant short-term psychological risks. Test-related distress was reduced among those who learned that they were APOE epsilon4-negative. Persons with high levels of emotional distress before undergoing genetic testing were more likely to have emotional difficulties after disclosure. (ClinicalTrials.gov number, NCT00571025.)

Genetic susceptibility testing versus family history-based risk assessment: Impact on perceived risk of Alzheimer disease.

PURPOSE: We examined how an Alzheimer disease (AD) family history assessment as compared to a risk assessment incorporating the absence of a disease-associated susceptibility allele affected risk perception among adult children with a family history of AD. METHODS: The REVEAL study is a clinical trial in which adult children of patients with AD were randomized to receive a risk assessment based upon family history alone or family history plus apolipoprotein E (APOE) disclosure. In this analysis, two subsets of women were identified, each of whom received identical 29% lifetime risk estimates of developing AD. One group received a risk estimate that incorporated APOE epsilon4-negative genetic test results (Genotype Group, n = 30), whereas the other received a risk estimate based on family history and gender (Family History Group, n = 36). Six weeks after risk disclosure, we surveyed participants regarding the impact of the risk assessment on their perceptions of AD risk. RESULTS: 73% of the Genotype Group judged their risk to be lower compared to 25% of the Family History Group (P < 0.0001). 67% of the Genotype Group reported lower anxiety about AD, versus 26% of the Family History Group (P < 0.01). 80% of the Genotype Group indicated that the risk information had a positive impact, versus 36% of the Family History Group (P < 0.001). The Genotype Group was less likely to believe that they would develop AD (13% vs. 36%, P < 0.05) and was more likely to report that the risk assessment removed uncertainty about their chances of developing AD (63% vs. 9%, P < 0.0001). CONCLUSIONS: These data suggest that risk estimates incorporating negative genetic test results affect perceptions of disease susceptibility more strongly than identical estimates based on family history alone.

Reasons for seeking genetic susceptibility testing among first-degree relatives of people with Alzheimer disease.

Advances in genetic research have provided a basis for susceptibility testing for Alzheimer disease (AD). Prior surveys have examined attitudes toward genetic testing for AD in hypothetical scenarios, but it is unclear what reasons would motivate people to seek testing in real-life situations. This study presents data from the first randomized trial to evaluate genetic susceptibility testing for asymptomatic adult children of people with AD. We examined (1) reasons endorsed as motivations for seeking testing, (2) demographic characteristics associated with these reasons, and (3) how these reasons related to the eventual decision to pursue testing. Eligible participants were 206 adult children of people with AD (mean age 53 years; 72% female; 93% white), 77.7% of whom (n = 160) went on to seek testing. Participants endorsed numerous reasons for seeking susceptibility testing (mean 7.2), encompassing a range of motivations. The most commonly endorsed reasons were as follows: (1) to contribute to research (93.9%), (2) to arrange personal affairs (87.4%), and (3) the hope that effective treatment will be developed (86.8%). Women strongly endorsed more reasons for seeking testing than men (p < 0.05). The best predictor of actual pursuit of testing was strong endorsement of the need to prepare family members for AD (odds ratio = 3.3, p < 0.01). Findings suggest that genetic susceptibility testing is of interest to individuals at risk for AD for a variety of reasons, even in the relative absence of available treatments.

Who seeks genetic susceptibility testing for Alzheimer's disease? Findings from a multisite, randomized clinical trial.

PURPOSE: Alzheimer's disease, for which one form of the apolipoprotein E (APOE) genotype is a risk factor, provides a paradigm in which to examine response to susceptibility testing for common, complex diseases. This study's main purposes were to estimate interest in such testing and to examine demographic predictors of study participation. METHODS: In this 3-site, randomized clinical trial (RCT), the intervention was a risk assessment program wherein genetic counselors educated adult children of AD patients about lifetime risk of disease based on their gender, family history, and APOE genotype. Two groups of participants were followed from initial contact to RCT enrollment: those who were systematically contacted through research registries, and those who were self-referred. RESULTS: Of 196 systematically contacted participants, 47, or 24%, progressed from initial contact to RCT enrollment. These participants were more likely to be below age 60 (adjusted OR = 3.83, P < 0.01) and college educated (adjusted OR = 3.48, P < 0.01). Of 179 self-referred participants, 115, or 64%, progressed from initial contact to RCT enrollment. Most self-referred participants had a college education and were female (79%). CONCLUSIONS: In the first RCT to examine genetic susceptibility testing for AD, uptake rates were sufficiently high to merit concern that future test demand may strain available education and counseling resources. Findings suggest that susceptibility testing for AD may be of particular interest to women, college educated persons, and persons below age 60.