Description
Both incidence and prevalence studies ha e
confirmed an association between
carriers of the ApoE ε4 allele and the
development of late onset Alzheimer’s Disease.
That this association is causal is supported by
evidence of a dose effect of the ApoE ε4 allele
and the findings of a number of studies
suggesting a protective role of the ApoE ε2 allele.
Possession of the ApoE ε4 allele carries a
significant risk in population terms. In
prevalence studies this amounts to an
approximately three times increased risk in ApoE
ε4 heterozygotes and a nine times increased risk
in ApoE ε4 homozygotes. However, the
importance of the ApoE ε4 allele in increasing an
individual ’s risk of developing Alzheimer’s
Disease remains uncertain because of a number
of factors including gender, nationality, gene-
gene and gene-environmental interactions which
can influence personal risk.
