ABSTRACT
BACKGROUND: It is unclear whether the APOE epsilon4 allele is associated with distinct clinical features in dementia. METHOD: 100 cases meeting ICD criteria for dementia were interviewed using standardized instruments and genotyped for APOE. The presence of the epsilon4 allele was used by a genetic algorithm neural network (GANN) to discriminate symptoms and signs. RESULTS: The GANN selected six features: gender, systolic blood pressure, absence of ankle tendon reflexes, history of weight loss, history of falls, and interviewer observed lability of mood. Using these features, a neural network discriminated cases according to epsilon4 highly accurately (area under receiver operating characteristic=0.83, sensitivity=0.78, specificity=0.78). CONCLUSIONS: A GANN is able to discriminate a clinically distinct group of features among dementia patients who express the epsilon4 allele.
Subject(s)
Algorithms , Apolipoproteins E/genetics , Dementia/genetics , Neural Networks, Computer , Accidental Falls , Affect , Aged , Aged, 80 and over , Apolipoprotein E4 , Apolipoproteins E/analysis , Blood Pressure , Dementia/diagnosis , Dementia/physiopathology , Diagnosis, Differential , Female , Humans , Male , Reflex, Abnormal , Risk Factors , Sex Factors , Weight LossABSTRACT
OBJECTIVE: The aims of this study were (a) to determine the frequency of APOE genotypes in dementia, (b) to relate e4 allele frequency to clinical symptomatology of dementia and (c) to relate e4 and assess risk factors for different types of dementia. DESIGN: Prospective clinical study setting older patients with dementia known to a community-based old age psychiatry service. SAMPLE: 101 patients fulfilling ICD 10 criteria for dementia. RESULTS: Replication of previous findings of an association between APOE4 and Alzheimer's disease: younger age of onset of dementia; family history of dementia; persecutory ideation; and (retrospectively determined) rate of competent decline. No association was found between APOE4 and vascular dementia. The association between APOE4 and 'mixed dementia' was intermediate between that of pure Alzheimer's disease and pure vascular dementia. CONCLUSION: The results confirm the relationship between clinical features of dementia and APOE4 status. It may be that APOE can be used as an adjunct to clinical diagnosis.
Subject(s)
Apolipoproteins E/genetics , Dementia/genetics , Aged , Aged, 80 and over , Dementia/physiopathology , Dementia/psychology , Female , Genetic Markers , Genotype , Humans , Male , Middle Aged , Risk FactorsABSTRACT
OBJECTIVE: Assessment of apolipoprotein E genotype, serum cholesterol, triglycerides, high density lipoprotein-cholesterol and low density lipoprotein-cholesterol levels in different types of dementia. SUBJECTS: 102 consecutive referrals to an old age psychiatry service based at Manchester were classified according to clinical criteria based on ICD 10. RESULTS: Thirty-seven were considered to have Alzheimer's disease, 16 multi-infarct dementia and 33 to be free from dementia. Sixteen patients, in whom a definitive diagnosis could not be reached or sufficient information was not available, were excluded from the study. There was an increase in the prevalence of the Apo E4 allele in both Alzheimer's disease (chi 2 = 3.82, p < 0.05) and multi-infarct dementia (chi 2 = 1.93, p < 0. = 0.16) by Wald tests compared to individuals without dementia. The increased prevalence of the E4 Allele in multi-infarct dementia was not related to serum lipid levels. CONCLUSION: The hypothesis that the onset of multi-infarct dementia may be precipitated by E4's mediation of higher serum cholesterol levels is not supported by the present study.