Alpha1-antichymotrypsin polymorphism in Japanese cases of Alzheimer's disease.

We examined the possible involvement of alpha1-antichymotrypsin (ACT) polymorphism in the risk for Alzheimer's disease (AD) in a Japanese population. No differences between AD and control subjects have been shown in the genotype distributions and allele frequencies of ACT. No modification of the risk for AD was observed, either alone or in combination with the apolipoprotein epsilon4 (ApoE-4) allele. Our results from a Japanese population failed to confirm the previous data in which the ACT polymorphism was shown to affect the ApoE-4-associated risk for AD.