Absence of association of α₁-antichymotrypsin polymorphisms with Alzheimer's disease: A report on autopsy-confirmed cases

α₁-Antichymotrypsin (ACT) polymorphisms were examined in 79 cases with autopsy-confirmed Alzheimer's disease (AD) as well as in 28 cases with autopsy-confirmed nonneurological diseases to test the hypothesis that ACT polymorphisms confer a risk to an individual to develop AD. Neither ACT genotype frequency nor ACT allele frequency in the AD group was significantly different from the control group. The ACT polymorphic pattern was essentially the same among apolipoprotein E (apoE) ε4 carriers and noncarriers. The age at onset of AD was not significantly affected by the inherited dose of ACT/A allele. Taking together, our observations do not confirm the effect of the ACT/A allele as a risk factor for developing AD in addition to the ApoE ε4 allele.