Blood type gene locus has no influence on ACE association with Alzheimer's disease.

The ABO blood group locus was recently found to contribute independently and via interactions with angiotensin-converting enzyme (ACE) gene variation to plasma levels of ACE. Variation in ACE has previously been not only implicated as individually conferring susceptibility for Alzheimer's disease (AD) but also proposed to confer risk via interactions with other as yet unknown genes. More recently, larger studies have not supported ACE as a risk factor for AD, whereas the role of ACE pathway in AD has come under increased levels of scrutiny with respect to various aspects of AD pathology and possible therapies. We explored the potential combined involvement of ABO and ACE variations in the genetic susceptibility of 2067 AD cases compared with 1376 nondemented elderly. Including the effects of ABO haplotype did not provide any evidence for the genetic association of ACE with AD.