There exists considerable evidence implicating abnormalities of the alpha (
alpha)-adrenergic system in the development of Alzheimer disease (AD). We p
ropose to investigate potential correlations between the presence or otherw
ise of alpha -adrenoceptor polymorphisms and the presence of AD. We studied
the polymorphisms of the alpha (1a)- and the alpha (2a)-adrenoceptor genes
in 142 AD patients and 98 normal controls. The result demonstrated that no
ne of the alpha (2a)-adrenoceptor genotypes was associated with increased s
usceptibility to AD. However, there was a trend that the frequency of the C
allele of the alpha (1a)-adrenoceptor was elevated and an excess of the CC
genotype (90.1%) was found in the subjects with AD in comparison with the
controls (78.6%). This association was unrelated to the apolipoprotein E ge
notypes. The hypothesis that the alpha (1a)-adrenoceptor gene may be implic
ated in the pathogenesis of AD may deserve further study.