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Letters

Genetics consortiums can offer views facilitating best practice in Alzheimer's disease

BMJ 1998; 317 doi: https://doi.org/10.1136/bmj.317.7156.471 (Published 15 August 1998) Cite this as: BMJ 1998;317:471
  1. Simon Lovestone, Chair of United Kingdom Alzheimer's Disease Genetics Consortium
  1. Institute of Psychiatry, London SE5 8AF

    EDITOR—Alzheimer's disease is often taken as an example of a disorder for which the impact of the new genetics will be met, 1 2 and it was with this in mind that the United Kingdom Alzheimer's Disease Genetics Consortium was formed. Members of the consortium are clinicians involved in both genetics and dementia care, academics, members of lay organisations, and representatives from pharmaceutical research; they meet to consider the consequences of the growing understanding of genetics in Alzheimer's disease. Through the consortium we have participated in the discussions referred to by Gill and Richards,3 have suggested measures to ensure the ethical conduct of genetic research,4 and are encouraging the coordinated provision of clinical genetic services for early onset familial Alzheimer's disease. More importantly, however, the collective view of the consortium has helped clinicians facing requests for genetic testing for late onset Alzheimer's disease; current data suggest that apolipoprotein E genotyping offers little in the way of prediction.

    Whether apolipoprotein E genotyping should be used to aid diagnosis is more controversial than Bell suggests.1 While some people have recommended apolipoprotein E genotyping in diagnosis, other consensus groups have come to the contrary view. The United Kingdom Alzheimer's Disease Genetics Consortium is concerned that the criteria to be expected from an adjunctive diagnostic test have not yet been met and that possible adverse consequences of diagnostic testing, although not as great as those of predictive testing, should not be ignored. Genetic tests are not the same as other tests because information may be relevant to other family members. Apolipoprotein E4 homozygosity in a patient with dementia increases the probability of a diagnosis of Alzheimer's disease but simultaneously doubles the lifetime risk for 65 year old first degree relatives of the patient. The consequences for the provision of long term care costs and the implications for any insurance are considerable.2

    Careful consideration of the impact of genetic testing is important, and this includes diagnostic tests. While waiting for research on strategies to respond to genetic testing, as suggested by Marteau and Croyle,5 groups such as the United Kingdom Alzheimer's Disease Genetics Consortium can offer a collective view which, though not substituting for empirical evidence, can facilitate best practice. If other such groups are established this will raise questions regarding coordination and dissemination. Perhaps there is a role here for the genetics advisory commission or the Department of Health.

    References

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