Genetics and Alzheimer's disease
Genetics is the study of how a specific characteristic, such as a disease, is passed from one generation to another. The role of genetics in Alzheimer's disease is a subject of intense study for scientists and a major concern for people with Alzheimer's disease and their families.
Alzheimer's disease can be grouped into two types: Familial Autosomal Dominant Alzheimer's Disease (FAD) and Sporadic Alzheimer's Disease.
There are two types of genetic investigation of a disease. Each has its limitations.
For people with Alzheimer's disease and their families:
Decision to be tested or not: Predictive genetic testing for Alzheimer's disease is an option only for people in families with a history of FAD. The decision whether or not to undergo genetic testing is difficult for many people. Will the information help people make decisions about personal relationships, having children, financial and lifestyle choices? Also, do people want to know their chances of developing a disease for which there may be treatment for symptoms but currently no cure and no prevention? What effect will this information have on the individual and other family members? For example, will it affect their access to insurance and employment benefits?
Right to know versus the right not to know: Within a family, one person may want to know whether or not he carries the gene or genetic risk factors for Alzheimer's disease; another may not. However, the assessment of one family member may reveal genetic information about other family members. Should informed consent be obtained from all family members before any type of genetic testing can occur?
Right to privacy and confidentiality: Who should be notified of the results of genetic testing? Should family members, insurance companies and employers be able to obtain the results? Should the information be kept confidential? Should the person who has been tested be allowed to prevent others from getting the results?
Potential exploitation of a person's desire to know: Some people are willing to buy any test that promises to tell the future, whether or not the test is sound or is accompanied by the essential components of consent, counselling and confidentiality. How should the potential exploitation of people concerned about developing Alzheimer's disease be addressed?
What does this mean for families concerned about Alzheimer's disease?
The field of genetics is a growing one. Each day, scientists are learning more about our genetic makeup. The challenge remains that, with every new discovery, consideration must be given to the effects on individuals, their families and society in general.
For the vast majority of people concerned about developing Alzheimer's disease, there is, at present, no test to determine if a specific unaffected person will or will not develop Alzheimer's disease.
For the small number of people for whom predictive testing is possible, the decision to know or not to know is a personal one. However, it should only be made in a setting that allows for informed consent, counselling and confidentiality.
Concerned individuals should contact the Alzheimer Society or their local clinical genetics unit for more information.
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