 |
AGS POSITION STATEMENT Genetic Testing for Late-Onset Alzheimer’s Disease AGS Ethics Committee *Last Updated in 2000* BACKGROUND Genes associated with Alzheimer’s disease (AD) have been identified, and genetic tests for specific gene mutations (such as APP, PS1, PS2) and alleles (such as APOE) are commercially available. Geriatricians now face decisions about the appropriateness of genetic testing for patients either at risk for, or with symptoms of AD. In addition, the rapid pace of genetic research and the decoding of the human genome suggests that many new genes will be identified over the next decade, a number of which could be related to late-onset disorders and common chronic diseases that affect older adults. Medical professionals and the lay public have demonstrated a great interest in genetic testing, but also have expressed concerns about potential misuses. Geriatric health care professionals are therefore likely to confront a number of ethical issues raised by the use of genetic tests. Several other professional organizations have published consensus guidelines for the use of genetic tests for AD, and also describe some of the ethical issues raised(1-5). Although the American Geriatrics Society (AGS) does not endorse any specific guideline, geriatricians and health professionals who wish to utilize genetic testing for late onset disorders are encouraged to be familiar with such guidelines. The aim of this position statement is to highlight ethical issues related to genetic testing that are commonly seen in geriatric clinical practice. POSITIONS 1. At the present time, the role of genetic testing for the prevention, diagnosis, and treatment of late-onset disorders is uncertain. Until further information is available to clearly define the benefits of genetic testing for conditions such as AD, physicians should not routinely order genetic tests for late-onset disorders. As with any medical test, the decision regarding the utility of a genetic test should consider the benefits to the individual patient and the ways that a test result would modify the care that the patient would receive. Rationale: AD is the most common late-onset disorder for which genetic information is available. AD is a genetically heterogeneous disorder, which currently is known to be associated with three causal genes (APP, PS1, and PS2) and one susceptibility gene (APOE). The causal genes are associated only with familial AD, which affects less than 10% of AD patients. The usefulness of APOE for prediction or diagnosis remains controversial. Therefore, use of these tests should not be included in routine clinical evaluations of patients with dementia. However, in cases in which the family history is suggestive of familial AD, patients may wish to undergo genetic counseling and testing and these procedures should be made available through appropriate referrals.
2. Geriatricians and genetic counselors need to be cognizant of the unique challenges related to informed consent for genetic testing in older adults. Rationale: Very little, if anything, is known about the "genetic literacy" of older adults. Preliminary research performed with younger populations suggests that even many young adults, whose formal education occurred after the discovery of DNA, do not understand some of the basic concepts related to genetic testing. Most older adults attended school prior to the discovery of DNA, did not encounter prenatal genetic testing during childbearing years, and therefore may have an even more limited understanding of genetic concepts. Geriatric health care professionals and genetic counselors need to consider this when explaining genetic testing to patients, and they may need to modify explanations and educational materials, as indicated. Patients suspected of having dementia may lack the capacity to provide informed consent for a genetic test, and this needs to be evaluated carefully. Decision-making is also complicated by the fact that information from a genetic test of an affected patient may have probabilistic implications for family members. Geriatric health care professionals need to be aware of, and sensitive to, the impact that decisions about genetic testing may have on other family members. When the patient is unable to provide informed consent, the decision maker will often be a family member; most commonly a child who shares 50% of the patient¢ s genes, or a spouse who has no direct biological relationship to the patient but may have children with the patient. In such cases, the decision-makers could be in a position to be affected by the predictive implications of a test. Indeed, what may be a diagnostic test for an affected patient may also be a predictive test for that individual’s children. Concerns by family members about probabilistic implications of genetic tests are to be expected. Inclusion of family members in the decision-making process may help to allay such concerns and may facilitate decisions about genetic testing even when the patient does not require a surrogate. However, the primary focus of genetic counseling and the decision-making process should be on the benefits and burdens of testing for the affected patient. Although only one family member may serve as the surrogate decision-maker, involvement of other family members in such decisions should be encouraged whenever possible.
3. Decisions about ordering genetic tests should consider the burden of other competing morbidities experienced by the patient. Rationale: Older adults are more likely to have a number of chronic illnesses and a shorter expected lifespan. Genetic testing for late-onset disorders may not outweigh the benefits if: 1) the patient is unlikely to develop a disorder predicted by a genetic test because of an anticipated shortened life expectancy or; 2) medical treatment would not be altered by test results because the burden of any indicated treatment outweighs the benefit in relation to the individual’s current medical conditions and personal preferences.
4. Geriatricians who wish to utilize genetic testing in their practice should acquire the requisite knowledge and skills. Rationale: Medical genetics is an emerging field and most geriatric health professionals, unless recently trained, have minimal education in genetics. As with any medical technology, it is imperative that physicians who use genetic testing in their clinical practice be well educated in this area, so that they can apply the technology appropriately and communicate effectively with patients and families. They should be able to articulate the difference between diagnostic and predictive genetic testing. They should understand the sensitivity and specificity of a particular genetic test and how other risk factors might affect an individual’s risk. In addition to understanding the technical aspects of genetic testing, geriatric health professionals should be knowledgeable about the requirements of informed consent for genetic testing and effective genetic counseling.
5. The use of genetic testing raises the possibility that such information may also be used by insurance companies, such that long-term care (LTC) insurance could be denied to individuals who test positive for genes that are predictive or diagnostic of late-onset disorders such as AD. Federal policies need to be developed to ensure the privacy of genetic information and to protect individuals from discrimination by insurance companies based on genetic test results. Rationale: The need and demand for LTC services will dramatically increase over this century and persons with AD are at high risk for the provision of such services. LTC services present a substantial financial risk and burden to individuals and their families. At the present time private LTC insurance covers only a small percentage of the costs of LTC. This type of insurance is increasingly being marketed to provide some financial support for LTC. Patients with known AD are usually ineligible to purchase LTC insurance. The availability of predictive genetic tests raises the possibility that they will be used by insurance companies to determine eligibility for policies and premium rates. This type of discriminatory practice should be prohibited. REFERENCES (1) Brodaty H, Conneally M, Gauthier S, Jennings C, Lennox A, Lovestone S. Consensus statement on predictive testing for Alzheimer disease. Alz Dis Assoc Disord 1995; 9(4):182-187. (2) American College of Medical Genetics/American Society of Human Genetics Working Group. Statement on use of apolipoprotein E testing for Alzheimer disease. JAMA 1995; 274(20):1627-1629. (3) Post SG, Whitehouse PJ, Binstock RH, et al. The clinical introduction of genetic testing for Alzheimer's disease. JAMA 1997; 277(10):832-836. (4) Predisposition genetic testing for
late-onset disorders in adults. a position paper of the National
Society of Genetic Counselors. JAMA 1997; 278(15):1217 This AGS position statement was developed and reviewed by the AGS Ethics Committee and approved November, 2000, by the AGS Board of Directors. The AGS thanks Ellen Binder, MD for her work on this position statement. Address corrspondence to: American Geriatrics Society, the Empire State Building, 350 Fifth Avenue, Suite 801, New York, NY 10118, Fax: 212-832-8646, info.amger@americangeriatrics.org
|
 |