Apolipoprotein E: non-cognitive symptoms and cognitive decline in late onset Alzheimer's disease.

Objective: To determine the association between the epsilon2 and epsilon4 alleles of apolipoprotein E (ApoE) and independent measures of cognitive decline and non-cognitive symptomatology in late onset Alzheimer's disease.

Methods: The frequency of the epsilon2 and epsilon4 alleles of ApoE and their association with measures of cognitive decline and non-cognitive symptomatology were assessed in a population based case register study of 164 patients with late onset Alzheimer's disease from the east Lambeth and south Southwark districts of south London.

Results: Analysis of a wide range of non-cognitive symptoms against ApoE epsilon4 genotype showed no significant association but a positive relation was found between ApoE epsilon2 genotype and depressive symptomatology (P = 0.004). No relation was found between measurements of cognitive decline and the presence of the ApoE epsilon4 allele. A trend for decreasing age at onset of 3 to 4 years in carriers of the ApoE epsilon4 allele was found, confirming earlier studies.

Conclusions: Presence of the epsilon4 allele of ApoE is associated with an earlier age at onset but does not seem to be related to either a more severe psychopathology or a more rapid progression of the illness. The epsilon2 allele of ApoE is associated with depressive symptomatology in late onset Alzheimer's disease.