title: Genetic risk of Alzheimer's disease: advising relatives.
abstract: BACKGROUND
  Clinicians are increasingly asked by relatives of patients with Alzheimer's disease to advise on their genetic risk of developing Alzheimer's disease in later life. Many clinicians find this a difficult question to answer.
  
  
  OBJECTIVE
  To provide information for old age psychiatrists wishing to advise relatives of their risk of developing Alzheimer's disease.
  
  
  METHODS
  A selective review of the key literature on the genetic epidemiology of Alzheimer's disease.
  
  
  RESULTS
  Currently a DNA diagnosis is attainable in some 70% of families with autosomal dominant Alzheimer's disease. In first-degree relatives of most cases, risk is increased some three- or four-fold relative to controls, but only one-third of this is realised in the average life span. Apolipoprotein E genotyping cannot be used as a predictive test and confers only minimal diagnostic benefit.
  
  
  CONCLUSIONS
  Pedigrees with familial Alzheimer's disease should be referred to a Regional Centre for Medical Genetics. Accurate risk prediction is not possible in the vast majority of pedigrees with Alzheimer's disease, although it is possible for the psychiatrist to give a rough estimate of the risk, which can reasonably the couched in reassuring terms.
authors.affiliation: Department of Psychological Medicine, University of Wales College of Medicine, Cardiff, UK. liddellmb@cardiff.ac.uk
authors.forename: M B
authors.initials: MB
authors.lastname: Liddell
authors.forename: S
authors.initials: S
authors.lastname: Lovestone
authors.forename: M J
authors.initials: MJ
authors.lastname: Owen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis / Q000235:genetics*; D001057:Apolipoproteins E / Q000235:genetics; D005817:Genetic Counseling; D005820:Genetic Testing; D005838:Genotype; D006801:Humans; D010375:Pedigree; D012307:Risk Factors
chemical_list: D001057:Apolipoproteins E