Association analysis of the partially duplicated alpha7 nicotinic acetylcholine receptor genetic variant and Alzheimer's disease.

Changes in the nicotinic acetylcholine receptors (nAChRs) have been demonstrated for Alzheimer's disease (AD). Of these receptors, the alpha7 nAChRs, which are abundant on hippocampal interneurons, have been implicated in the cytotoxic role of the beta-amyloid. Increased mRNA levels of alpha7 nAChR in the peripheral lymphocytes and hippocampus of AD patients have been reported. We tested the hypothesis that the allelic variant, 2bp deletion, of the partially duplicated alpha7 nAChR gene confers susceptibility to Alzheimer's disease. The -2bp polymorphism was examined in 120 patients with AD and 98 normal controls. The distribution of the partially duplicated alpha7 nAChR genotypes (p = 0.372) and alleles (p = 0.465) did not differ significantly for AD patients and controls. This negative finding suggests that the partially duplicated alpha7 nAChR genetic polymorphism contributes no major effect to the development of AD. However, we suggest that the other genetic variation of the alpha7 nAChR gene, related to AD or the associated symptomatology, merits further investigation.