Association of alpha1-antichymotrypsin polymorphism with cerebral amyloid angiopathy.

In search of genetic risk factors of sporadic cerebral amyloid angiopathy (CAA), we investigated the association of a polymorphism in the signal peptide sequence of alpha1-antichymotrypsin (ACT) with the severity of CAA in 155 autopsy cases of the elderly, including 48 patients with Alzheimer's disease. In the total cases, there was no significant association of the ACT genotypes (AA, AT, and TT) with the severity of CAA. Within the Alzheimer's disease group, however, a significant correlation was found between the ACT A allele frequency and the severity of CAA.